Question

The amount of radioactive uranium changes with time. The table below shows the amount of radioactive uranium f(t) left after time t:


t(hours) 0 0.5 1
f(t) 100 50 25


Which exponential function best represents the relationship between f(t) and t?

Answer 1

@mathstudent55
@hba

Answer 2

at every half of increase of time the amount of radioactive material is also half

Answer 3

f(t) = 100(0.25)t

f(t) = 0.25(100)t

f(t) = 100 (0.5)t

f(t) = 0.25(50)t

Answer 4

those are the chocies ^^^

Answer 5

Look at you choices.
Insert each given point in all your choices.
The choice that works for all points is the answer.

Answer 6

I dont understand how to do it

Answer 7

oh wait is it d

Answer 8

Point 1 is (0, 100)
Let's try point 1 in choice 1:

f(t) = 100(0.25)t
f(0) = 100(0.25)^0 = 100 * 1 = 100

Choice 1 works for point 1

Answer 9

Now we need to test point 2 in choice 1.

Answer 10

Point 2 is (0.5, 50)

Choice 1 is
f(t) = 100(0.25)t
so we get
f(0.5) = 100(0.25)^0.5 = 100 * 0.5 = 50

It works.

Answer 11

Let's try point 3 with choice 1.
Point 3 is (1, 25)

f(t) = 100(0.25)t
f(1) = 100(0.25)^1 = 100 * 0.25 = 25

It also works.

This is the answer.

Answer 12

thanks!! so much!!!

Answer 13

wlcm

Answer 14

what was the anwser?