Respuesta :

9514 1404 393

Answer:

  a) 13%

  b) 65.9%

Step-by-step explanation:

a) You can use n=1 to find the percentage remaining at the end of 1 hour:

  P = 100(0.87^1) = 87

This is 13% less than 100%, so the decay rate per hour is 13%.

__

b) Fill in n=3 and evaluate the expression.

  P = 100(0.87^3) = 65.8503

After 3 hours, about 65.9% of the caffeine remains.