Question

Curt just drank a cup of coffee to help him stay awake. The coffee had 130 milligrams of caffeine in it. If his body processes 7% of the caffeine every hour, how much will be left in 4 hours?

93
94
98
91

Answer 1

After 4 hours, his body will have processed 28% because 7*4 = 28. But, you're trying to find what's left (so, subtract that % from 100)100%-28% = 72%Then multiply the percent left by the total number of milligrams of caffeine130*.72 = 93.6 mg

Answer 2

93,6mg

Explanation:

Every hour he will process 7% of the intial caffeine dose (130mg), so every hour the boy wil process 9,1mg.

In the 4th hour he had processed 4*9,1mg = 36,4mg, so in his doy will be left

130mg - 36,4mg = 93,6mg