So w of zero, well we know that, that's the bounds are gonna be zero to zero, they even gave that to us in the problem, is the initial state is we have 30 cubic feet of water in the pipe already. And now what is w of eight? Well this is going to be 30 plus the definite integral from zero to eight of r of x minus d of x minus d of x dx. And lucky for us, we're allowed to use a calculator, so let's use a calculator to evaluate this. And so let me get my calculator out, and actually let me go see the definitions of r of x and d of x right over here so I can type them in. And what I'm gonna do, and there's a bunch of ways, the more advanced you get with a calculator that might save you some time if you're on the AP test, I'm gonna actually define a function that is r of x minus d of x. So everywhere I see a t, I'm gonna substitute it, I'm gonna use an x instead.