5.5 is the answer for the problem
The answer is 10 because its in the tens place
72ft
you do 8 times 2 is 16
34-16 is 18 then divide by 2 is 9
9 times 8 is 72
~JZ
To calculate the remaining caffeine, we use the radioactive decay formula which is expressed as An = Aoe^-kt where An is the amount left after t time, Ao is the initial amount and k is a constant we can calculate from the half-life information. We do as follows:
at half-life,
ln 1/2 = -k(6)
k = 0.12/hr
An = 80e^-0.12(14)
An = 15.87 mg
