The​ half-life of a radioactive substance is 20 years. If you start with some amount of this​ substance, what fraction will remain in 180 years?

Answers

Answer 1

Answer:

1/512

Step-by-step explanation:

Let staring fraction = x

Half-life = 20 years ; this is the time taken for an element to decrease to half of its original size

Hence,

After 20 years - - - > x/2

After 40 years - - - - > x/2 ÷ 2 = x/2 * 1/2 = x /4

After 60 years - - - - > x/4 ÷ 2 = x/4 * 1/2 = x/8

After 80 years - - - - -> x/8 ÷ 2 = x/8 * 1/2 = x / 16

After 100 years - - - > x/16 * 1/2 = x/32

After 120 years - - - - > x/32 * 1/2 = x/64

After 140 years - - - - -> x / 64 * 1/2 = x / 128

After 160 years - - - - - > x / 128 * 1/2 = x/256

After 180 years - - - - > x/256 * 1/2 = x / 512

Hence, the fraction after 180 years = 1/512


Related Questions

An oil company is going to issue new ID codes to its employees. Each code will have one letter, followed by one digit, followed by three letters. The letters w, x, y, and z will not be used. So, there are 22 letters and 10 digits that will be used. Assume that the letters can be repeated. How many employee ID codes can be generated?

Answers

Answer:

2342560 combos

Step-by-step explanation:

so its 1 letter*1number*1 letter*1 letter*1 letter, or 22x10x22x22x22 which should equate to 2342560 possible ID codes, hope this helps :)

What is the mean of the following list of extra credit points earned on a statistics test?
10,8,18,17,7

Answers

Answer:

12

Step-by-step explanation:

Given the data :

X : 10,8,18,17,7

The mean value of scores obtained can be obtained thus :

Mean = ΣX / n

n = sample size = 5

Mean = ΣX / n = (10+8+18+17+7) / 5

Mean = 60 / 5 = 12

please help, will give brainliest!!!!

Answers

Answer:

3

Step-by-step explanation:

3 - 3/x

----------------

1 - 1/x

Multiply the top and bottom by x

x(3 - 3/x)

----------------

x(1 - 1/x)

3x -3

------------

x-1

Factor the numerator

3(x-1)

-------

x-1

Cancel like terms

3

-----

1

3

Bod and coa are _____ angles

Answers

Answer:

opposite angles

Step-by-step explanation:

They are formed in the intersection of lines AD and BD.

Answer:

opposite angles

Step-by-step explanation:

they are formed in the intersection of lines AD and BD. two figures are called similar if they have same shape however have different size.

6) Frazer cycles the first 20 miles at an average speed of 21mph. The second
part is more uphill, and he only manages 13mph. By what percentage did his
speed decrease?
How to solve

Answers

9514 1404 393

Answer:

  38.1% decrease

Step-by-step explanation:

A percentage change is found from ...

  % change = (change)/(original amount) × 100%

  = (new value - original amount)/(original amount) × 100%

  = (13 -21)/21 × 100% = -8/21 × 100% ≈ -38.1%

Frazer's speed decreased by 38.1% during the second part.

_____

Additional comment

A negative % change represents a decrease; a positive % change represents an increase.

which function is positive for the entire interval (-3,-2)

Answers

Answer:

There can be several such functions; however, the basic condition that needs to be met for a function to be positive for the interval [–3, –2] is that it should be multiplied by (-1) Hence, one such function that is positive for the entire interval is f(x) = -x

Step-by-step explanation:

A.Yes, since the slopes are the same and the y-intercepts are the same.
B.No, since the y-intercepts are different.
C.Yes, since the slopes are the same and the y-intercepts are different.
D.No, since the slopes are different.

Answers

Answer:

C

Step-by-step explanation:

one line is

y = 3x/7 + 11

its slope is 3/7

the y-intercept is, of course, when x=0. there y=11

the other is

-3x + 7y = 13

7y = 3x + 13

y = 3x/7 + 13/7

its slope is 3/7 (the same as the other line)

the y-intercept (x=0) is y = 13/7 (different to the other line)

Answer:

C. Yes, since the slopes are the same and the y-intercepts are different.

Step-by-step explanation:

[tex]y=\frac{3}{7} x+11[/tex]  and [tex]-3x+7y=13[/tex]

→ Rearrange the second equation to make y the subject

7y = 3x + 13

→ Divide everything by 7

[tex]y=\frac{3}{7} x+\frac{13}{7}[/tex]

What is the total cost of a $28 pair of jeans if the sales tax is 7.5%?

Answers

Answer:

30.10

Step-by-step explanation:

First find the amount of tax

28 * 7.5%

28 * .075

2.10

Add this to the price of the pants

28+2.10 =30.10


f(x) = x - 1. Find the inverse of f(x).

Answers

Answer:

f^-1 (x) = x+1

Step-by-step explanation:

f(x) = x-1

y = x-1

Exchange x and y

x = y-1

Solve for y

Add 1 to each side

x+1 = y-1+1

x+1 = y

The inverse is x+1

f^-1 (x) = x+1

find the missing side length in the image below​

Answers

Answer:

3/6=?/10

Step-by-step explanation:

multiply by together. ?=5

what is factorization of the trinomial below? -x2+2x+48

Answers

Answer:

-(x+6) (x-8)

Step-by-step explanation:

-(x^2-2x-48)

two values the multiply to get 48 and the difference of those two numbers gives you -2.

6,-8

6 x -8 =-48

6-8=-2

In this case we factored out the negative so leave it outside

-(x+6) (x-8)

Answer:

-1(x-8)(x+6) is the answer just took the test

Step-by-step explanation:

i need help ON THIS PLS

Answers

Answer:

No, because the ratio of pay to hours is not the same for each pair of value.

Which equation describes this graph?

Answers

Step-by-step explanation:

The graph clearly has a positive slope. So Answer D couldn't be correct. Next: the y-intercept of this line is (0, -2), so b in the formula y = mx÷ b must be -2.

Therefore the correct equation of this line is

y = x - 2 (choice a)

. Using the identity (a + b)² = (a² + 2ab + b²), evaluate 112²



Answers

[tex]\\ \sf\longmapsto 112^2[/tex]

[tex]\\ \sf\longmapsto (100+12)^2[/tex]

[tex]\\ \sf\longmapsto 100^2+2(100)(12)+12^2[/tex]

[tex]\\ \sf\longmapsto 10000+2400+144[/tex]

[tex]\\ \sf\longmapsto 12400+144[/tex]

[tex]\\ \sf\longmapsto 12544[/tex]

112²

Using Identity

(a + b)² = (a² + 2ab + b²)

Solution

⇛112²

⇛(100 + 12)²

⇛(100)² + 2 × 100 × 12 + (12)²

⇛10000 + 2400 + 144

⇛12400 + 144

⇛12544

If the nominal rate of interest is 10% per annum and there is quarterly compounding, the effective rate of interest will be: a) 10% per annum b) 10.10 per annum c) 10.25%per annum d) 10.38% per annum​

Answers

9514 1404 393

Answer:

  d) 10.38%

Step-by-step explanation:

The multiplier for four quarters of quarterly compounding is ...

  (1 +10%/4)^4 = 1.025^4 = 1.103812890625

This is about 1 + 10.38%.

The effective rate of interest is about 10.38% per annum.

Select the statement that best justifies the conclusion based on the given information.

a. Definition of bisector.
b. Definition of midpoint.
c. If two lines intersect, then their intersection is exactly one point.
d. Through any two different points, exactly one line exists.

Answers

9514 1404 393

Answer:

  a. Definition of bisector.

Step-by-step explanation:

Line l is a line through the midpoint M. We can conclude it is a bisector, because, by definition, a bisector is a line through the midpoint.

The conclusion is justified by the definition of a bisector.

Find the equation (in terms of x) of the line through the points (-2,-3) and (4,-1)

Answers

Answer:

y = 1/3x - 7/3

Step-by-step explanation:

y2 - y1 / x2 - x1

-1 - (-3) / 4 - (-2)

2/6

= 1/3

y = 1/3x + b

-1 = 1/3(4) + b

-1 = 4/3 + b

-7/3 = b

For the function G defined by G(x) = 5x + 3, find G(2)

Answers

G(x)=5x+3

[tex]\\ \sf\longmapsto G(2)[/tex]

[tex]\\ \sf\longmapsto 5(2)+3[/tex]

[tex]\\ \sf\longmapsto 10+3[/tex]

[tex]\\ \sf\longmapsto 13[/tex]

Option c is correct

13, replace x as 2 and then solve, 5(2)+3 which is 10+3 which equals 13.

FX) is defined by the equation f(x) = 4x2 - 2x +17. What effect will multiplying
f(x) by 0.5 have on the graph?
A. The graph will be stretched horizontally.
B. The graph will be compressed horizontally.
C. The graph will be stretched vertically.
D. The graph will be compressed vertically.

Answers

Step-by-step explanation:

the graph will be compressed vertically

Copy center charges $0.08 a page for machine fed copies and $0.20 for hand fed copies.If Logan's bill for 80 copies of his movie script is $13, how many copies of each type were made?

Answers

Answer:

machine fed copies = 25, hand fed copies = 55

Step-by-step explanation:

let machine fed = x, hand fed = y

0.08x+0.2y = 13 (1)

x+y = 80

x= 80-y (2)

sub (2) into (1)

0.08(80-y)+0.2y=13

6.4-0.08y+0.2y=13

0.12y=6.6

y = 55

sub y=55 into eqn 2

x = 80-55 = 25

Please
Help me asap!!

Answers

Answer:

z -2 = 10

Step-by-step explanation:

11z-9-10z+7 = 10

Combine like terms on the left side

11z -10z     -9+7  =10

z -2 = 10

Answer: z=12

Step-by-step explanation:

[tex]11z-9-10z+7=10\\z-9+7=10\\z-2=10\\z=12[/tex]

Assume that two marbles are drawn without replacement from a box with 1 blue, 3 white, 2 green, and 2 red marbles. Find the probability that the first marble is white and the second marble is blue.

Answers

Answer:

3/56

Step-by-step explanation:

Probability is the ratio of the number of possible outcome to the number of total outcome.

Given that two marbles are drawn without replacement from a box with 1 blue, 3 white, 2 green, and 2 red marbles.

The total number of marbles in the box

= 1 + 3 + 2 + 2

= 8 marbles

The probability that the first marble is white and the second marble is blue

= 3/8 * 1/7

= 3/56

What is the slope of a roof on a house that has a vertical height of 2.4 feet from the ceiling of the top floor to the top of the pitch and a length of 8.2 feet from the center of the edge of the house?

Answers

Answer:

Step-by-step explanation:

It is unclear from the phrasing what dimension 8.2 ft represents.

If 8.2 ft is the direct distance from the edge of the roof to the top of the pitch, then the horizontal distance from the edge to the top is √(8.2²-2.4²) ≅ 7.84 ft, and the slope is 2.4/7.84 ≅ 0.31

If 8.2 ft is the horizontal distance from the edge of the root to the top of the pitch, then the slope is 2.4/8.2 ≅ 0.29

The slope of a roof on a house is 0.2926 and the angle of elevation is 16.31°.

What is slope of a line?

The slope or gradient of a line is a number that describes both the direction X and Y and the steepness of the line. It is the ratio of the vertical change to the horizontal change between any two distinct points on a line.

For the given situation,

The diagram below shows the house with the roof.

The vertical height of roof on a house, rise = 2.4 feet

The horizontal length of a roof on a house, run = 8.2 feet

The slope of a roof can be found as

[tex]Slope = \frac{rise}{run}[/tex]

⇒ [tex]slope = (\frac{2.4}{8.2} )[/tex]

⇒ [tex]slope = 0.2926[/tex]

The angle of the slope of a roof can be found as

[tex]tan \alpha =\frac{vertical height}{horizontal length}[/tex]

⇒ [tex]\alpha =tan^{-1} (\frac{2.4}{8.2} )[/tex]

⇒ [tex]\alpha =tan^{-1} (0.2926)[/tex]

⇒ [tex]\alpha =16.31[/tex]

Hence we can conclude that the slope of a roof on a house is 0.2926 and the angle of elevation is 16.31°.

Learn more about slope of a line here

https://brainly.com/question/6204743

#SPJ2

Express as index form
log 2 64 = 6

Answers

Answer:

hsv s deutsche ki bhar ke dekhte hai mera gham na

Write each percent as a fraction in simple form 15 3/5%

Answers

Answer:

39/250

Step-by-step explanation:

15 3/5 = 78/5 and percent means per 100, so

(78/5)/100 = (78/5)(1/100)

=78/500 = 39/250

find x on this special right triangle, 45 is not an option!!!!

Answers

let the line between 2 tria be y

sin 60/8√2 = sin 90/y

y=13.06

sin 45/13.06 = sin 90/x

x=18.46

Answer:

First, find the hypotenuse of the right triangle with the 60° & 30°.

Hypotenuse = hsin(x) = opposite side/hypotenuse

[tex]sin(60) = \frac{8\sqrt{2}}{h} \\\\sin(60)h=8\sqrt{2}\\\\\frac{\sqrt{3}}{2} h=8\sqrt{2}\\\\h=\frac{8\sqrt{2}}{\frac{\sqrt{3}}{2}}=8\sqrt{2}*\frac{2}{\sqrt{3}} =\frac{16\sqrt{2} }{\sqrt{3}} =\frac{16\sqrt{2}(\sqrt{3}) }{\sqrt{3}(\sqrt{3})} =\frac{16\sqrt{6} }{3}[/tex]

Use that side length to find x.

sin(x) = opposite side/hypotenuse

[tex]sin(45)=\frac{\frac{16\sqrt{6}}{3}}{x}\\\\sin(45)x=\frac{16\sqrt{6}}{3} \\\\\frac{\sqrt{2}}{2}x=\frac{16\sqrt{6}}{3} \\\\x=\frac{\frac{16\sqrt{6}}{3}}{\frac{\sqrt{2}}{2}}=\frac{16\sqrt{6}}{3}*\frac{2}{\sqrt{2}}=\frac{16\sqrt{2}\sqrt{3}(2)}{3\sqrt{2} }=\frac{32\sqrt{3} }{3}[/tex]

AM and CM
BM and BM
AB and CB

Answers

These are variables on your graph

Researchers studied symptom distress and palliative care designation among a sample of 710 hospitalized patients. Controlling for age, they used a t-test to compare average distress from nausea scores in men and women. Lower scores indicated less distress from nausea. They report men had an average score of 1.02 and woman had an average score of 1.79. Which statement is correct?
(2pts)
Select Men had significantly less distress from nausea. as your answer
Men had significantly less distress from nausea.
Select Men had half as much distress from nausea as woman but we can not determine if this is a significant difference. as your answer
Men had half as much distress from nausea as woman but we can not determine if this is a significant difference.
Select Men had less distress from nausea on average than women but we can not determine if this is a significant difference. as your answer
Men had less distress from nausea on average than women but we can not determine if this is a significant difference.
Select There is a positive correlation between distress from nausea and gender. as your answer
There is a positive correlation between distress from nausea and gender.

Answers

Answer:

A. Men had less distress from nausea on average than women but we can not determine if this is a significant difference.

Step-by-step explanation:

Working based on the information given, the mean values of each group with with men having an average score of 1.02 and women have an average of 1.79 this reveals that distressing nausea on average is higher in women than in men . However, to test if there is a significant difference would be challenging as the information given isn't enough to make proceed with the test as the standard deviations of the two groups aren't given and no accompanying sample data is given.

can someone help me, please?

Answers

Answer:

0

2

-1

Step-by-step explanation:

from f(0) we find that

y = mx - 1

from f(-1) we find that the equation is

y = -3x - 1

1)

inverse f(x) :

x = -3y - 1

y = -(x + 1) / 3           x = -1

y = -(-1 + 1) / 3

y = 0

2)

y also equal to 0 since x = -1

3)

f^-1(2) = -(2+1) / 3

          = -3/3

          = -1

f(-1) =  2

How much more area does a large pizza with a 12 in. diameter have than a small pizza with an 8 in. diameter? Round your answer to the nearest square inch.

Answers

Answer: About 63 in²

Step-by-step explanation:

Area of circle = π · r²

r = radius lengthπ ≈ 3.14

Area of large pizza:

[tex]\pi *r^{2} =3.14*6^{2} =3.14*36=113.04[/tex]

Area of small pizza:

[tex]\pi *r^{2} =3.14*4^{2} =3.14*16=50.24[/tex]

Difference in area:

[tex]113.04-50.24=62.8[/tex]

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