Need some help?

Question

Assume a quantity decreased by 7.6 % in 8.5 hours.
What is the half-life of the substance?

Answer 1

dependng on what class you are taking...
depends on the method to use
the decay factor is .924
you are looking for when .924^x= .5
solve using logs or by guess and check
when x is 9
gives 0.924^9=.49...so about 1/2
so after 9 times of decreasing by 7.6%
so 9*8.5 is76.5 hours

Answer 2

7.6/8.5 = 50/x

X = 55.921 hours.

Answer 3

exp(-8.5/hl)=.924 assuming you mean continuous decay.
-8.5/hl=ln(.924)....hl=-8.5/ln(.924)=107.5 hours (approximately).