The percentage of a certain brand of computer chips that will fail after t years of use is estimated to be

Question

P(t) = 100(1 − e−0.12t ).
What percentage of this brand of computer chips are expected to be usable after 3 years? (Round your answer to one decimal place.)

Answer 1

just plug in t = 3

P(3) = 100(1 - e^-.36)
= 30.23

So appr 30.2%

Answer 2

This is what I got too, but it says that my answer is wrong.

Answer 3

100 - 30.2

Answer 4

You percent is percent that will FAIL
It asks for the ones that do not fail.

Answer 5

Ahh, looks like neither one of us read the question carefully.
P(t) given the percentage that will FAIL, which is 30.2%

But it says, "what percentage ... is usable "

so 100 - 30.2 or 69.8%

Answer 6

Thanks for the help.