First one is correct hope this helped
Firstly, solve 38C15.
Then solve 42C12.
Compare your answers.
The goal here is to see if 38C15 = 42C12.
Here is the formula:
nCr = n!/(r!(n - r)!
Go for it.
Answer:
∴35.97 mg caffeine would be left in the system after 5 hours.
Step-by-step explanation:
Given that,
A cup of coffee has approximately 310 mg of caffeine.
Caffeine decrease at a rate 35% per hour.
Exponential Function:

y(t)= Amount caffeine after t hours
= Initial amount of caffeine
r= rate of decrease
t = Time in hour.
Here y(t)=?,
= 310 mg, r=35%=0.35, t= 5 hours

=35.97 mg
∴35.97 mg caffeine would be left in the system after 5 hours.
No, It is not. Factor out 2 from it