Question

Assume the half-life of a substance is 34 days and the initial amount is 116.399999999999 grams.
(a) Fill in the right hand side of the following equation which expresses the amount A of the substance as a function of time t (the coefficient of t in the exponent should have at least four significant digits):
A=
(b) When will the substance be reduced to 2 grams? (feel free to use decimals if needed.)
t=

Answer 1

16.399999999999 ????? , really?

A = 16.4(.5)^(t/34)

you want A = 2
2 = 16.4(.5)^(t/34) , where t is in days
2/16.4 = .5^(t/34)
log (1/8.2) = (t/34)log(.5)

see if you can get t = 103.21 days