For the same interval, right over here, there are 30 cubic feet of water in the pipe at time t equals 0. Part a. How many cubic feet of rainwater flow into the pipe during the 8 hour time interval 0 is less than or equal to t is less than or equal to 8? Alright, so we know the rate, the rate that things flow into the rainwater pipe. In fact, we could, let me draw a little rainwater pipe here just so we can visualize what's going on. So if this is, if that is the pipe right over there, things are flowing in at a rate of r of t, and things are flowing out at a rate of d of t, and they even tell us that there's 30 cubic feet of water right in the beginning. But these are the rates of entering and the rates of exiting.