Answer:
[tex]P(t) = 100e^{0.0251t}[/tex]
The doubling time is of 27.65 minutes.
Step-by-step explanation:
Exponential equation of growth:
The exponential equation for population growth is given by:
[tex]P(t) = P(0)e^{kt}[/tex]
In which P(0) is the initial value and k is the growth rate.
A freshly inoculated bacterial culture of Streptococcus contains 100 cells.
This means that [tex]P(0) = 100[/tex]. So
[tex]P(t) = 100e^{kt}[/tex]
When the culture is checked 60 minutes later, it is determined that there are 450 cells present.
This means that [tex]P(60) = 450[/tex], and we use this to find k. So
[tex]450 = 100e^{60k}[/tex]
[tex]e^{60k} = 4.5[/tex]
[tex]\ln{e^{60k}} = \ln{4.5}[/tex]
[tex]60k = \ln{4.5}[/tex]
[tex]k = \frac{\ln{4.5}}{60}[/tex]
[tex]k = 0.0251[/tex]
So
[tex]P(t) = 100e^{0.0251t}[/tex]
Doubling time:
This is t for which P(t) = 2P(0) = 200. So
[tex]200 = 100e^{0.0251t}[/tex]
[tex]e^{0.0251t} = 2[/tex]
[tex]\ln{e^{0.0251t}} = \ln{2}[/tex]
[tex]0.0251t = \ln{2}[/tex]
[tex]t = \frac{\ln{2}}{0.0251}[/tex]
[tex]t = 27.65[/tex]
The doubling time is of 27.65 minutes.
At what rates did she invest?
$1400 invested at ____%
$900 invested at ____%
9514 1404 393
Answer:
$1400 at 8%$900 at 10%Step-by-step explanation:
The 1-year interest is simply the invested amount times the interest rate.
Let r represent the lower interest rate. Then r+0.02 is the higher rate, and the total interest earned is ...
1400r + 900(r +.02) = 202
2300r +18 = 202 . . . . . . . . . .simplify
2300r = 184 . . . . . . . . . .subtract 18
r = 184/2300 = 0.08 = 8% . . . . . . divide by the coefficient of r
$1400 was invested at 8%.
$900 was invested at 10%.
1. Samuel paid #34.20 for a blanket. If the marked price of the blanket is #41.78. What is the discount?
2. A mother buys a dress for her daughter at a discount of 18%. If the price of the dress is #35.00. How does she actually pay for the dress?
Answer:
1. The discount is 10%
2. 250
Help please ……………….zzzz
1) I think 15 choose (d)
2) The choose (C) -4fg+4g
3) The choose (d) 3xy/2
4) The choose (a) ab/6
5) The choose (C) 2p+4q-6
6)
[tex]\pi {r}^{2} h = 3.14 \times {3}^{2} \times 1.5 = 42.39 {m}^{3} = 42.390 {m}^{3} [/tex]
Point 6 I think there is an error because the unit m must be m³ because it is r² (m²) and h(m) becomes m³.
I hope I helped you^_^
I need this please pleaseeee nowww
Answer:
y = 3x - 5
Step-by-step explanation:
Slope = 3
x-intercept (what the value of y is when its 0) = -5 so y = 3x - 5
Answer:
y = 3x - 5
Step-by-step explanation:
Find the slope of the line between (0,−5)(0,-5) and (3,4)(3,4) using m=y2−y1x2−x1m=y2-y1x2-x1, which is the change of yy over the change of xx.
m=3m=3
Use the slope 33 and a given point (0,−5)(0,-5) to substitute for x1x1 and y1y1 in the point-slope form y−y1=m(x−x1)y-y1=m(x-x1), which is derived from the slope equation m=y2−y1x2−x1m=y2-y1x2-x1.
y−(−5)=3⋅(x−(0))y-(-5)=3⋅(x-(0))
Simplify the equation and keep it in point-slope form.
y+5=3⋅(x+0)
Add xx and 00.
y+5=3xy+5=3x
Subtract 55 from both sides of the equation.
y=3x−5
You need 675 mL of a 90% alcohol solution. On hand, you have a 25% alcohol mixture. How much of the 25% alcohol mixture and pure alcohol will you need to obtain the desired solution?
Answer:
90 ml of the 25 percent mixture and 585 of pure alcohol
Step-by-step explanation:
Firstly, you should find the quantity of alcohol in the desired mixture.
675:100*90= 675*0.9= 607.5
Firstly, define all the 25 percents mixure as x, the pure alcohol weight is y.
1. x+y= 675 (because the first and the second liquid form a desired liquid).
Then find the equation for spirit
The first mixture contains 25 percents. It is x/100*25= 0.25x
When the second one consists of pure alcohol, it contains 100 percents of spirit, so it is x.
2. 0.25x+y=607.5
Then you have a system of equations ( 1.x+y= 675 and 2. 0.25x+y= 607.5)
try 2-1 to get rid of y
x+y- (0.25x+y)= 675-607.5
0.75x= 67.5
x= 90
y= 675-x= 675-90= 585
It means that you need90 ml of the 25percents mixture and 585 0f pure alcohol
find the answer for 10 points
Answer:
52.8
Step-by-step explanation:
(3×2.6×2/2)+(3×5×3)
= 7.8+45
= 52.8
Answered by GAUTHMATH
Write the inequality shown in this graph.
Answer:
y > -1/2 x + 4
Step-by-step explanation:
Equation of a line : (y-y1)/(y2-y1) = (x-x1)/(x2-x1)
(y-4)/(2-4)= (x-0)/(4-0)
(y-4)/-2 = x/4
(-y+4)/2 = x/4
-y+4 = 1/2 x
-y = 1/2 x - 4
y = -1/2 x + 4
the solutions of the inequality are the points above this line, so
y > -1/2 x + 4
5(2x-5) = 1/2(18x+40)
Answer:
x = 45
Step-by-step explanation:
5 (2x - 5) = 1/2 (18x + 40)
10x - 25 = 9x + 20
10x = 9x + 45
x = 45
please mark this answer as brainlist
Solve each equation for the specified variable
Answer: Solve for the specified variables
Step-by-step explanation:
1. w= A/l
2. d=C/pi
3. s=v-gt
4. y= 5/2x-11/2
5. P^2= P^1V^1 / P^2 Put ^ as lowercase as shown, can't find symbol on my keboard T.T
6. W= Ke2g / V^2
7. h= V / 2/3 pi r^2
8. n=2S/a+k
9. S=A/pi r - r (not 100% sure on that one)
10. r= E/I-R
11. h= E-1/2mv^2/mg
12. a=K+5b/b+3
13. c=ab/b+a
Wooh, finally finished all that. Hope I didn't make any mistakes. Have a great day!
What is the equation of the parabola shown in the graph?
Answer:
[tex]-\frac{x^{2} }{4}[/tex] -2x - 7
Step-by-step explanation:
Never seen a phone with 3 cameras before or something but ok.
Took a while to use brainly's insert character thingie since fractions and the exponent kinda threw me off.
Help please 6x + 3 > a if the inequality above is true for the constant a which of the following. coupd be a vakue of z
Answer:
[tex]\frac{a+3}{6}[/tex]
Step-by-step explanation:
Treat it like any other math problem with a equals sign:
6x + 3 = a
subtract 3 from both sides: 6x = a + 3
divide both sides by 6: [tex]x = \frac{a+3}{6}[/tex]
swap the ≥ back in: [tex]x \geq \frac{a+3}{6}[/tex]
the only time the sign flips is if you divide by a negative
for any Integer 'a',a ÷ 0 is _______
give me answer
Answer:
undefined, invalid
and for a limit expression like a/x, x->0 we also say this is infinite.
find the squre of 17
[tex] \sqrt{17} [/tex]
if x-y =2 and xy=15, find the value of x cube - y cube.
Answer:
5³ = 125 : -3³ = -27Step-by-step explanation:
let x= 5 and y= 3x - y = 25 - 3 = 2xy = 155 × 3 = 15x³ = ? : -y³ = ?5³ = 125 : -3³ = -27[tex]\tt{ \green{P} \orange{s} \red{y} \blue{x} \pink{c} \purple{h} \green{i} e}[/tex]
A woman is 42years old. Her daughter is 1/3 of her age. Three years ago the sum of her age was
Answer:
50
Step-by-step explanation:
So we know that 42/3=14.
3 years before was:
14-3=11
42-3=39
The sum of 11+39 is 50
A runner sprinted for 414 feet. How many yards is this?
Answer:
138 yards
Step-by-step explanation:
1 feet is (1/3) yard
414 feet is (1/3)*414=138 yards
Evaluate the expression when x = 12/7
The value of the expression when x equals is ???
PLEASE HELP!!
Answer:
82
Step-by-step explanation:
1/3( x+9/7) + 3^4
Let x = 12/7
1/3( 12/7+9/7) + 3^4
PEMDAS says parentheses first
1/3( 21/7) + 3^4
1/3(3) +3^4
Then exponents
1/3(3)+81
Then multiply
1+81
82
Hey good morning I need help ASAP thank you guys
Answer:
B. x = 2.77
Step-by-step explanation:
3^x = 21
You first look for a base for 21 that is 3 to the power of something.
21 = 3^2.77
So 3^x = 2^2.77
They have the same base so
x= 2.77
Find the measure of ZJ, the smallest angle in a triangle
with sides measuring 11, 13, and 19. Round to the
nearest whole degree.
O 30°
O 34°
o 42°
O 47°
Which point on the number line shows the graph
Answer:
B
Step-by-step explanation:
X ^2 + 2x + y’ + 6y = 15
Step-by-step explanation:
x^2+2x+7y=15
7y=15-x^2-2x
y=15/7-1/7x^2-2/7x , x ∈ all real numbers
18 Geometry question: Use an algebraic equation to find the measure of each angle that is representative in terms of X
Answer:
12x - 28° = 116°
7x + 32° = 116°
Step-by-step explanation:
12x - 28° and 7x + 32° are vertical angles. Vertical angles are congruent.
Therefore, to find the measure of each angle, we have to set each equation equal to each other as follows:
12x - 28° = 7x + 32°
Collect like terms
12x - 7x = 28 + 32
5x = 60
Divide both sides by 5
5x/5 = 60/5
x = 12
✔️12x - 28°
Plug in the value of x
12(12) - 28
= 144 - 28
= 116°
✔️7x + 32°
7(12) + 32
= 84 + 32
= 116°
What is the distance between the following points?
Will give brainliest
Answer:
√65
Step-by-step explanation:
(-6,4) (-5,-4)
√(x2 - x1)² + (y2 - y1)²
√[-5 - (-6)]² + (-4 - 4)²
√(1)² + (-8)²
√1 + 64
√65
Use the listing method to represent the following set. Hurry plz!!!
[tex]\\ \sf\longmapsto \left\{x|x \epsilon I,x\leqslant 3\right\}[/tex]
Here x belongs to set of Integersx is less than or equal to 3In listing
[tex]\\ \sf\longmapsto \left\{\dots,0,1,2,3\right\}[/tex]
I need help figuring out this equation
270 degrees is at the bottom of the unit circle, and it splits the 3rd and 4th quadrants.
Its terminal point is (0, -1).
Hope this helps!
Answer:
A. (0, -1)
Step-by-step explanation:
This question requires a chart to answer. The chart is inserted in the answer.
270 degrees is all the way at the bottom, at South which shows that 270 degrees is at (0, -1).
Meaning, the answer is A, (0, -1).
Hope this helped.
A certain test preparation course is designed to help students improve their scores on the LSAT exam. A mock exam is given at the beginning and end of the course to determine the effectiveness of the course. The following measurements are the net change in 5 students' scores on the exam after completing the course: 16, 21, 22, 12, 22
Using these data, construct a 90% confidence interval for the average net change in a student's score after completing the course. Assume the population is approximately normal. Find the critical value that should be used in constructing the confidence interval. Round your answer to three decimal places.
Answer:
The critical value used is [tex]T_c = 2.132[/tex]
The 90% confidence interval for the average net change in a student's score after completing the course is (14.357, 22.843).
Step-by-step explanation:
Before building the confidence interval, we need to find the sample mean and the sample standard deviation.
Sample mean:
[tex]\overline{x} = \frac{16+21+22+12+22}{5} = 18.6[/tex]
Sample standard deviation:
[tex]s = \sqrt{\frac{(16-18.6)^2+(21-18.6)^2+(22-18.6)^2+(12-18.6)^2+(22-18.6)^2}{4}} = 4.45[/tex]
Confidence interval:
We have the standard deviation for the sample, so the t-distribution is used to solve this question.
The first step to solve this problem is finding how many degrees of freedom,which is the sample size subtracted by 1. So
df = 5 - 1 = 4
90% confidence interval
Now, we have to find a value of T, which is found looking at the t table, with 4 degrees of freedom(y-axis) and a confidence level of [tex]1 - \frac{1 - 0.9}{2} = 0.95[/tex]. So we have T = 2.132. The critical value used is [tex]T_c = 2.132[/tex]
The margin of error is:
[tex]M = T\frac{s}{\sqrt{n}} = 2.132\frac{4.45}{\sqrt{5}} = 4.243[/tex]
In which s is the standard deviation of the sample and n is the size of the sample.
The lower end of the interval is the sample mean subtracted by M. So it is 18.6 - 4.243 = 14.357
The upper end of the interval is the sample mean added to M. So it is 18.6 + 4.243 = 22.843.
The 90% confidence interval for the average net change in a student's score after completing the course is (14.357, 22.843).
solve for x . please help also don’t forget to show work
Answer:
X-4x+11=8
-3x+12-8=0
-3x+4=0
3x=4
X=4/3
Answer:
x = 4/3 or 1.3
Step-by-step explanation:
Combine like terms
8 = -3x + 12
Move the terms
3x = 12 - 8
Calculate
3x = 4
Divide both sides by 3
x = 4/3
or
x = 1.3
Two professors are applying for grants. Professor Jane has a probability of 0.64 of being funded. Professor Joe has probability 0.28 of being funded. Since the grants are submitted to two different federal agencies, assume the outcomes for each grant are independent.
Required:
a. What is the probability that both professors get their grantsfunded?
b. What is the probability that at least one of the professors will befunded?
c. What is the probability that Professor Jane is funded but ProfessorJoe is not?
d. Given at least one of the professors is funded, what is theprobability that Professor Jane is funded but Professor Joe is not?
please help me
no links or files
thank you !
Jane is saving to buy a cell phone. She is given a $100 gift to start and saves $35 a month from her allowance. So after one month, Jane has saved $135. Does it make sense to represent the relationship between the amount saved and the number of months with one constant rate? Why or why not? Explain your answer.
Jane is given a $100 gift to start and saves $35 a month from her allowance.
After 1 month, Jane has saved
After 2 months, Jane has saved
After three months, Jane has saved
and so on
In general, after x months Jane has saved
This means that it makes sense to represent the relationship between the amount saved and the number of months with one constant rate (in this case the constant rate is 35). It makes sense because the amount of money increases by $35 each month. Since the amount of increase is constant, we get constant rate. Also the initial amount is known ($100), so there is a possibility to write the equation of linear function representing this situation.
Step-by-step explanation:
You and your friends have tickets to attend a music concert. While standing in line, the promoter states he will give a gift card for a free album download to each person that is a multiple of 2. He will also give a backstage pass to each fourth person and floor seats to each fifth person. Which person will receive the free album download, backstage pass, and floor seats? Explain the process you used to determine your answer.
9514 1404 393
Answer:
20th
Step-by-step explanation:
The person will receive all gifts if the are all of a multiple of 2, a multiple of 4, and a multiple of 5. Since 4 is already a multiple of 2, the person who will receive all is the one who is a multiple of 4 and 5.
20 is 4×5, so is a multiple of both numbers. There is no smaller number that is a multiple of both 4 and 5.
The 20th person will receive all gifts.
_____
The value we have determined here is called the "least common multiple" (LCM). It is the product of the unique prime factors of the numbers of interest, raised to the highest power that appears in any of the numbers.
2 = 2¹
4 = 2²
5 = 5¹
LCM(2, 4 5) = 2² × 5¹ = 20
