1) Maggie shook 100 pennies in a container and counted how many landed heads up. Approximately what fraction of pennies would you expect to land heads up? a) 1/4

b) 1/2

c) 3/4

d) 4/4

2) If three half-lives have passed, what fraction of the isotopes will still be parents?

a) 1/2

b) 1/4

c) 1/8

d) 1/16

3) A sample has a half-life of 1000 years. 1/4 of the isotopes are parents. How old is it?

a) 250 years

b) 500 years

c) 2000 years

d) 4000 years

4) A sample has a half-life of 1 million years. 1/8 of the isotopes are parents. How old is it?

a) 250,000 years

b) 500,000 years

c) 2 million years

d) 3 million years

(answer all and I will mark your answer the brainliest or you can just answer one)

the system of inequity is

step-by-step explanation:

from the given graph it is noticed that we have two related lines. one is solid and another is dashed.

if a line passing through two points, then the equation of line is

the solid line passing through the points (0,4) and (4,0).

the related equation of solid line is .

similarly, find the related equation of dashed line. the dashed liune passing through the points (0,0) and (3,1).

the related equation of dashed line is

from the given graph it is noticed that the point (0,1) lies on the shaded region, therefore the point (0,1) must be satisfied by the related equations.

check the related equations by the point (0,1).

this statement is true if the sign of inequality is < instead of equality. since it is an solid line therefore the sign of inequality will be . the required inequality is

similarly, check the second related equation.

it is a dashed line, so this statement is true if the sign of inequality is > . the required inequality is

any options?

step-by-step explanation:

a 4/6 = 9/12   not proportional

step-by-step explanation:

to find which are not proportional, we can use cross products

if it is true, they are proportional.   if it is not true, they are not proportional.

a 4/6 = 9/12

4* 12 = 6*9

48 = 54

not this is not proportional  

b 2/3 = 12/18  

2* 18 = 3 * 12

36 = 36

this is proportional

c 5/4 = 10/8  

5*8 = 4*10

40 = 40

this is proportional

d 7/5 = 35/25

7*25 = 5 * 35

175 = 175

is proportional