Getting each exercise correct gets you 8.3(recurring)%. Therefore if you answer 10 exercises correctly you get 83.3%, and if you answer 9 exercises correctly you get 75%, this means that the minimal exercises you need to get correct is 10.
A sample of 500 g of radioactive lead-210 decays to polonium-210 according to the function A(t)=500e^-0.032t , where t is time in years. Find the amount of radioactive lead remaining after (a) 3yr, (b) 8yr, (c) 10 yr. (d) Find the half-life.
Answer:
Step-by-step explanation:
Using the equation A(t) = 400e-.032t
a) replace t with 4 so A(4) = 400e((-.032)(4))
The hardest part about this is making sure to use order of operations. Be certain it works like this:
A(4) = 400e-.128
A(4) = 400(.8799)
A(4) = 351.9 grams
b) A(8) = 400e((-.032)(8)) = 309.7 grams
c) A(20) = 400e((-.032)(20)) = 210.9 grams
Note here that even after 20 years, not quite half of the original amount is gone. So, we can anticipate that in finding the half life, that our answer should be slightly greater than 20 years.
d) 200 = 400e(-.032t)
Divide both sides of the equation by 400.
.5 = e(-.032t)
Change this to logarithmic form.
Ln .5 = -.032t
-.6931≈ -.032t
t ≈ 21.7 years
Hope this helps!
The amount of radioactive lead,
(a).After 3 years is 454.23 grams
(b).After 8 years is 387.07 grams
(c).After 10 years is 363.07 grams.
(d). half life is 21.66 years.
The decay of radioactive lead is given by function,
[tex]A(t)=500e^{-0.032t}[/tex]
The amount of radioactive lead After 3 years is,
[tex]A(3)=500e^{-0.032*3}=0.908*500=454.23g[/tex]
The amount of radioactive lead After 8 years is,
[tex]A(8)=500e^{-0.032*8}=500*0.774=387.07g[/tex]
The amount of radioactive lead After 10 years is,
[tex]A(10)=500e^{-0.032*10}=500*0.726=363.07g[/tex]
Half life is defined as the interval of time required for one-half of the atomic nuclei of a radioactive sample to decay.
So, [tex]250=500e^{-0.032t}[/tex]
[tex]e^{-0.032t}=0.5\\\\-0.032t=ln(0.5)\\\\-0.032t=-0.693\\\\t=0.693/0.032=21.66 years[/tex]
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need help please. Will give you 5-stars and a big thank you comrades
Answer:
first answer
Step-by-step explanation:
(8x³ - 22x² - 4) / (4x - 3)
when you do long division you get the first answer
find the area of a rhombus with a 120 degree angle and sides 10 cm
Answer:
A = 50√3 cm²Step-by-step explanation:
[tex]A=s^2\cdot \sin\alpha\\\\s=10\\\alpha=120^o\\\\A=10^2\cdot\sin(120^o)=100\sin(180^o-60^o)=100\sin(60^o)=100\cdot\frac{\sqrt3}2=50\sqrt3[/tex]
Find f(x) and g(x) so the function can be expressed as y = f(g(x)). (1 point) [tex]y=\frac{7}{x^{2} } +10[/tex]
Answer:
The functions are [tex]f(x) = 7\cdot x+10[/tex] and [tex]g(x) = \frac{1}{x^{2}}[/tex], respectively.
Step-by-step explanation:
Let suppose that [tex]g(x) = \frac{1}{x^{2}}[/tex], then [tex]f(g(x))[/tex] is:
[tex]f(g(x)) = 7\cdot \left(\frac{1}{x^{2}} \right) + 10[/tex]
[tex]f(g(x)) = 7\cdot g(x) + 10[/tex]
Thus,
[tex]f(x) = 7\cdot x + 10[/tex]
The functions are [tex]f(x) = 7\cdot x+10[/tex] and [tex]g(x) = \frac{1}{x^{2}}[/tex], respectively.
What expression has the same value as -3/2-(2-3/8)+3/2
Answer:
[tex]\dfrac{-3}{2}-(2-\dfrac{3}{8})+\dfrac{3}{2}=\dfrac{-13}{8}[/tex]
Step-by-step explanation:
We need to find the value of expression [tex]\dfrac{-3}{2}-(2-\dfrac{3}{8})+\dfrac{3}{2}[/tex].
Firstly solving the second term as :
[tex](2-\dfrac{3}{8})=\dfrac{16-3}{8}=\dfrac{13}{8}[/tex]
Now the above expression becomes,
[tex]\dfrac{-3}{2}-(2-\dfrac{3}{8})+\dfrac{3}{2}\\=\dfrac{-3}{2}-\dfrac{13}{8}+\dfrac{3}{2}[/tex]
-3/2 and +3/2 equals 0.
It means that, [tex]\dfrac{-3}{2}-(2-\dfrac{3}{8})+\dfrac{3}{2}=\dfrac{-13}{8}[/tex]
solve 2(1/9)× = 2/81 for x
Answer: x=1/9
Step-by-step explanation:
[tex]2\left(\frac{1}{9}\right)x=\frac{2}{81}[/tex]
[tex]\frac{2}{9}x=\frac{2}{81}[/tex]
multiply both sides by 9
[tex]9\cdot \frac{2}{9}x=\frac{2\cdot \:9}{81}[/tex]
[tex]2x=\frac{2}{9}[/tex]
divide 2 on both sides
[tex]x=\frac{1}{9}[/tex]
Which of the following symbols could correctly finish the statement. Select all that apply. 0___-8 = ≠ > < ≥ ≤
Answer:
>
Step-by-step explanation:
Even though its 0 its still greater than any negative number.
Answer:
Step-by-step explanation:
Find the missing probability: P(B)=7/20, P(A|B)=1/4, P(A∩B)=?
Answer:
P(A∩B) = 7/80
P(A∩B) = 0.0875
Step-by-step explanation:
Given
P(B)=7/20
P(A|B)=¼
Required
P(A∩B)=?
The given probability shows conditional probability and the relationship between the given parameters is as follows.
P(A∩B) = P(B) * P(A|B)
Substitute ¼ for P(A|B) and 7/20 for P(B)
The expression
P(A∩B) = P(B) * P(A|B) becomes
P(A∩B) = 7/20 * ¼
P(A∩B) = 7/80
P(A∩B) = 0.0875
Hence, the calculated P(A∩B) is 7/80 or 0.0875
Name a real world context to describe the sums of rational numbers.
Step-by-step explanation:
when you are cooking you need to measure fractions of ingredients
what is the answer for 6x-4=-26+5x
Answer: x=-22
Step-by-step explanation:
6x-4=-26+5x
6x-4-5x=-26+5x-5x ⇔ subtraction property of equality
x-4=-26
x-4+4=-26+4 ⇔ addition property of equality
x=-22
Answer:
x = - 22Step-by-step explanation:
6x - 4 = - 26 + 5x
First of all group like terms
Send the constants to the right side of the equation and those with variables to the left
That's
6x - 5x = 4 - 26
Simplify
We have the final answer as
x = - 22Hope this helps you
What is the slope of the line?
A) -1/3
B) 1/3
C) -3
D) 3
Answer:
Hey there!
A simple way to think about slope is rise over run. Between any two points on this line, the rise is 3, and the run is -1.
3/-1=-3, so the slope is -3.
Let me know if this helps :)
Which expressions are equivalent to 2(b+3c)2(b+3c)2, left parenthesis, b, plus, 3, c, right parenthesis ?
Choose all answers that apply:
Choose all answers that apply:
(Choice A)
A
3(b+2c)3(b+2c)3, left parenthesis, b, plus, 2, c, right parenthesis
(Choice B)
B
(b+3c)+(b+3c)(b+3c)+(b+3c)left parenthesis, b, plus, 3, c, right parenthesis, plus, left parenthesis, b, plus, 3, c, right parenthesis
(Choice C)
C
2(b)+2(3c)2(b)+2(3c)2,
Answer:
B. (b+3c)+(b+3c) C. 2(b)+2(3c)Step-by-step explanation:
Given this expression 2(b+3c), its equivalent expression is derived by simply opening up the bracket as shown below;
Open the parenthesis by multiplying the constant outside the bracket with all the variables in parenthesis.
= 2(b+3c)
= 2(b)+ 2(3c)
= 2b +2*3*c
= 2b +6c
It can also be written as sum of b+3c in 2 places i.e (b+3c)+(b+3c) because multiplying the function b+3c by 2 means we are to add the function by itself in two places.
Hence the equivalent expression are (b+3c)+(b+3c) and 2(b)+2(3c) or 2b+6c
HELP ASAP ITS SO HARD! Kelsey did the following division problem. Her teacher says that the quotient she found is wrong. −2 5/6 ÷ 1 1/3 −17/6 ÷ 4/3 −6/17• 3/4 −6×3 divided by 17×4 −18/68 −9/34 A. Identify what Kelsey did wrong in her calculations. B. Find the correct quotient, showing all of your calculations.
Part A
Her steps were
[tex]-2 \frac{5}{6} \div 1 \frac{1}{3}\\\\-\frac{17}{6} \div \frac{4}{3}\\\\-\frac{6}{17} \times \frac{3}{4}\\\\-\frac{6\times 3}{17\times4}\\\\-\frac{18}{68}\\\\-\frac{9}{34}\\\\[/tex]
Kelsey made a mistake on line 3. Note how the 17/6 flips to 6/17. This is not correct. You keep the first fraction the same, but you do flip the second fraction. This only applies when you divide two fractions.
The third step should look like [tex]-\frac{17}{6}\times \frac{3}{4}[/tex]
=======================================================
Part B
Here's what she should have written
[tex]-2 \frac{5}{6} \div 1 \frac{1}{3}\\\\-\frac{17}{6} \div \frac{4}{3}\\\\-\frac{17}{6} \times \frac{3}{4}\\\\-\frac{17\times 3}{6\times 4}\\\\-\frac{51}{24}\\\\-\frac{17}{8}\\\\[/tex]
If you want to convert that improper fraction to a mixed number, then you could do something like this
[tex]-\frac{17}{8} = -\frac{16+1}{8}\\\\-\frac{17}{8} = -\frac{16}{8}-\frac{1}{8}\\\\-\frac{17}{8} = -2 \frac{1}{8}\\\\[/tex]
Or you could divide 17 over 8 using long division to get 2 remainder 1. The 2 is the quotient that goes to the left of the 1/8. The remainder of 1 is the numerator of 1/8.
help me im dangered plzzzzzzzzzzzzzzzzzzzz
Answer:
A
Step-by-step explanation:
Hi!
An exponent is the same thing as just multiplying the expression by itself the number of times the exponent says. So we need to multiply 1/3 by itself three times.
1/3 * 1/3 * 1/3 = 1/27
The Muller family are on holiday in New Zealand. a. They change some euros (€) and receive $1962 (New Zealand dollars). The exchange rate is €1 = $1.635. Calculate the number of euros they change. [3] b. The family spend 15% of their New Zealand dollars on a tour. Calculate the number of dollars they have left. [4]
Answer:
a. €1200;$1667.70
Step-by-step explanation:
a. Number of euros
[tex]\text{euros} = \$1962 \times \dfrac{\text{1 euro}}{\text{\$1.635}} = \textbf{1200 euros}[/tex]
b. Dollars remaining
Dollars on hand = $1962.00
Less 15 % spent = 0.15 × 1962 = -294.30
Balance remaining = $1667.70
Ten people were chosen at random and surveyed. The survey asked participants for the number of hours they sleep per night and the amount of their annual income. Letting X represent the number of hours the participant sleeps per night and Y represent the participant's annual income, the surveyor calculated the correlation coefficient between X and Y to be 0.29. Interpret the correlation coefficient calculated by choosing the statement below which correctly describes the correlation between X and Y. A. weak negative correlation B. strong negative correlation C. strong positive correlation D. weak positive correlation
Answer:
A. R=0.86; strong correlation
Step-by-step explanation:
The correlation coefficient of 0.29 indicates that the correlation is a weak positive correlation. Thus option (D) is the correct answer.
What is correlation?"Correlation is a statistical tool that studies the relationship between two variables. Data sets have a positive correlation when they increase together, and a negative correlation when one set increases as the other decreases".
For the given situation,
Correlation coefficient = 0.29
Positive correlation: the two variables change in the same direction.
Negative correlation: the two variables change in opposite directions.
No correlation: there is no association or relevant relationship between the two variables.
The correlation coefficient lies between 0 to 0.3 indicating that the correlation is a weak positive correlation.
Hence we can conclude that option (D) weak positive correlation is the correct answer.
Learn more about correlation here
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stagg high school has a rectangular swiming pool the area of the water in the pool is 1,800 meters squared the length is twice the width what is the perimeter of the pool find the length and width. SHOW WORK
Step-by-step explanation:
L*b=1800m^2
L=2b
2b*b=1800
2b^2=1800
b^2=900
b=30m
L=2*30
=60m
Perimeter=2(l+b)
=2(60+30)
=2*90
=180m
A can do a piece of work in 10 days and B in 12 days.
With the help of C they can finish the work in 4 days. How
long will C take to do it alone?
a) 12 days b) 15 days c) 18 days d) 20 days
Answer:
B. 15 days
Step-by-step explanation:
A=10=1/10 of the job
B=12=1/12 of the job
A+B+C=4=1/4 of the job
A+B
=1/10 + 1/12
=10+12/120
=22/120
=11/60
(A+B+C) - (A+B)
=1/4 - 11/60
=5 - 11/60
=4/60
=1/15
It would take C alone 15 days to finish the job
A sequence of transformations is described below. A reflection over a line \overleftrightarrow{PQ} PQ P, Q, with, \overleftrightarrow, on top A rotation about the point PPP Another reflection over \overleftrightarrow{PQ} PQ P, Q, with, \overleftrightarrow, on top A rotation about the point QQQ Which of the following must be preserved under this sequence of transformations? Choose 1 answer: Choose 1 answer: (Choice A) A Angle measures only (Choice B) B Segment lengths only (Choice C) C Both angle measures and segment lengths (Choice D) D Neither angle measures nor segment lengths
Answer:
The correct option is;
(Choice C) Both angle measures and segment lengths
Step-by-step explanation:
The given transformations are;
The reflection over the line, [tex]\overleftrightarrow{PQ}[/tex], with, A rotation about the point P. Another reflection over [tex]\overleftrightarrow{PQ}[/tex]. A rotation about the point Q, we have;
The transformations involve changes only in the orientation and location of the pre-image, which remain rigid, therefore, there are no changes in the segment lengths or angle dimensions
Therefore, the correct option is, both angle measures and segment lengths.
(Choice C) C Both angle measures and segment lengths
ASAP PLZ ANSWER!!! Can you tell me step by step to this question 8,595 ÷ 24?
Answer:
358 and remainder of 3
Step-by-step explanation:
1. Divide it like any other problem
24 goes into 85, 3 times with 13 left overBring down the 9 and 24 goes into 139, 5 times with 19 left overThen bring down the 5 and 24 goes inside 195, 8 times with 3 left overSo your remainder would be 3Hope this helps
Show all work to solve the equation for x. If a solution is extraneous, be sure to identify it in your final answer.
square root of the quantity x minus 3 end quantity plus 5 equals x
Answer:
Step-by-step explanation:
[tex]\sqrt{x-3} +5=x\\\sqrt{x-3} =x-5\\squaring ~both~sides\\x-3=x^2-10x+25\\x^2-10x-x+25+3=0\\x^2-11x+28=0\\x^2-7x-4x+28=0\\x(x-7)-4(x-7)=0\\(x-7)(x-4)=0\\x=7,4[/tex]
put x=7 in the given equation
[tex]\sqrt{7-3} +5=7\\\sqrt{4} +5=7\\2+5=7\\7=7[/tex]
which is true .
∴ x=7 is a solution of the given eq.
now put x=4 in the given eq.
[tex]\sqrt{4-3} +5=7\\1+5=7\\6=7\\[/tex]
which is not true.
∴x=4 is an extraneous solution.
An octagonal pyramid ... how many faces are there, how many vertices and how many edges? A triangular prism ... how many faces are there, how many vertices and how many edges? a triangular pyramid ... how many faces are there, how many vertices and how many edges?
1: 8 faces and 9 with the base 9 vertices and 16 edges
2: 3 faces and 5 with the bases 6 vertices and 9 edges
3: 3 faces and 4 with the base 4 vertices and 6 edges
1: 8 faces and 9 with the base 9 vertices and 16 edges
2: 3 faces and 5 with the bases 6 vertices and 9 edges
3: 3 faces and 4 with the base 4 vertices and 6 edges
Which data set matches the box-and-whisker plot?
A) 12 13 15 19 23 23 25 26.5 28 30
B) 15 13 19 21 23 24 27 29 32
C) 11 31 13 15 19 21 21 25 27 29 31
D) 11 13 15 19 23 23 24 26.5 28 33
Answer:
D) 11 13 15 19 23 23 24 26.5 28 33
Step-by-step explanation:
The box-and-whisker plot displayed above has the following key values that we can use to identify which of the given data set it matches. It has:
Minimum value = 11
Q1 = 15
Median = 23
Q3 = 26
Maximum value = 33
From the options given, using just the max and min value, we can conclude that the data set in option D matches the box plot.
The data set in option D has a minimum value of 11, and a maximum value of 33.
help help help me plZZZZZ ill give you brainly ;DDD
Answer:
the answer is 60.7
Step-by-step explanation:
60 to has a between numbers like given in the picture
so as number line it's
60.1 . 60.2 60.3 60.4 60.5 60.6 60.7 60.8 and continue
if u get any 3 digit number like 600 to 650 in number line
u do it like it the same 600.1 600.2.... and go on
Answer:
63½ or 63.5
Step-by-step explanation:
65-60=5
10points=5
1point=?
1×5/10= ½
that means the sequence continues after adding ½ i.e
60..60½...61...61½...62...62½...63...63½...64..64½...65
you have been asked the 8th number which is 63½
how to find the theta with side lengths of a triangle
Step-by-step explanation:
Hello, there!!!
I hope you mean the question is like the above problem in picture.
so, let's simply work with it.
here, we may use cosine rule,
so, according to cosine rule,
[tex] {c}^{2} = {a}^{2} + {b}^{2} - 2ab.cosc[/tex]
so, just put value of formulae here,
we get;
5^2 = 3^2 + 4^2 - (2×3×4) . cos thita
or, 25 = 9 + 16 -24 cos thita.
or, 24 cos thita = 0
or, cos thita = 0/25
or, cos thita = 0
now, taking cos to right side we get,
[tex] {cos}^{ - 1 } (0)[/tex]
now, after typing cos ^-1 (0) we get angle as 90°.
(note: in step {cos thita = 0} you couold directly write like; cos thita = cos 90°. and cos would be cancelled in it as cos 90°=0. but it is only applied in particular angle like 0°,30°,60°,..... which are identified or if you don't know you must use the method above using calculator and remember to put inverse {cos^-1}).
so, In this way we find angle.
I hope it helps....
How many solutions does this system of inequalities have graphed below
Answer:
There is only one solution set.
Step-by-step explanation:
The set can contain any number of solutions or none.
This is all I know, hope it helps.
Anna's back Garden consists of a rectangular lawn measuring 9m by 7m, surrounded by a gravel path of width X metres. Find, and simplify, an expression for the total area of the garden.
A rectangular lawn measuring 8m by 4m is surrounded by a flower bed of uniform width.
The combined area of the lawn and the flower bed is 165m^2. What is the width of the flower
:
Let x = the width of flower bed
:
Then the overall dimensions (flower bed & lawn) will be:
(2x + 8) by (2x + 4)
:
Overall area
(2x+8)*(2x+4) = 165
FOIL
4x^2 + 8x + 16x + 32 = 165
A quadratic equation
4x^2 + 24x + 32 - 165 = 0
4x^2 + 24x - 132 = 0
Simplify, divide by 4, results:
x^2 + 6x - 33 = 0
Use the quadratic formula to solve this
What is the area of this composite figure?
Answer:
C.) 7.14 in²
Step-by-step explanation:
The figure is made up of a square and a circle. The circle is divided in half and each piece is set on one side of the square. This means that the diameter of the circle is equal to the length of the sides of the square, 2 inches.
The area of the square can be found by multiplying length times the width:
[tex]2*2=4[/tex]
The area of the square is 4 inches, and since we multiplied two lengths, we square the value:
A=4in²
Now find the area of the circle using the formula:
[tex]A=\pi r^2[/tex]
The radius is half of the diameter, so the radius is 1. Insert values and solve:
[tex]A=\pi *1^2\\\\A=\pi *1\\\\A=\pi[/tex]
The area of the circle is equal to π. Add the values together:
[tex]4+\pi =7.14[/tex]
The area of the figure is 7.14 in²
:Done
1. Find the greatest common divisor of the term 144x3y2and 81xy4
Answer:
[tex]1296x^3y^4[/tex]
Step-by-step explanation:
Given the terms:
[tex]144x^3y^2[/tex]
and [tex]81xy^4[/tex]
To find:
Greatest Common Divisor of the two terms or Least Common Multiple (LCM) of two numbers = ?
Solution:
First of all, let us find the HCF (Highest Common Factor) for both the terms.
i.e. the terms which are common to both.
Let us factorize them.
[tex]144x^3y^2 = \underline{3 \times 3} \times 16\times \underline x \times x^{2}\times \underline{y^{2} }[/tex]
[tex]81xy^4= \underline {3\times 3}\times 9 \times \underline{x} \times \underline{y^2}\times y^2[/tex]
Common terms are underlined.
So, HCF of the terms = [tex]9xy^2[/tex]
Now, we know the property that product of two numbers is equal to the product of the numbers themselves.
HCF [tex]\times[/tex] LCM = [tex]144x^3y^2[/tex] [tex]\times[/tex] [tex]81xy^4[/tex]
[tex]LCM = \dfrac{144x^3y^2 \times 81xy^4}{9xy^2}\\\Rightarrow LCM = 144x^3y^2 \times 9x^{1-1}y^{4-2}\\\Rightarrow LCM = 144x^3y^2 \times 9x^{0}y^{2}\\\Rightarrow LCM = \bold{1296x^3y^4 }[/tex]
I also need to know this one pretty soon pleaseee
Answer:
128
Step-by-step explanation:
