1. The problem statement, all variables and given/known data An oil storage tank ruptures at time t = 0 and oil leaks from the tank at a rate of r(t) = 100 e^(-0.01t) liters per minute. How much oil leaks out during the first hour? 2. Relevant equations r(t) = 100 e^(-0.01t) 3. The attempt at a solution Eh, I already got the answer, I just did a definite integral from 0 to 60 for the equation. My question is: Why would you find the integral instead of just plugging in 60 for t into that equation? Is it because that equation is a rate, so it's a derivative and you have to take the integral to get the original equation?