Well, just remind ourselves, this is the rate of change of V with respect to time when time is equal to 16. So we can estimate it, and that's the key word here, estimate, we can estimate V prime of 16 by thinking about what is our change in velocity over our change in time around 16. When we look at it over here, they don't give us V of 16, but they give us V of 12, they give us V of 20. So let's figure out our rate of change between 12, T equals 12, and T equals 20. So our change in velocity, that's going to be V of 20 minus V of 12, and then our change in time is going to be 20 minus 12. And so this is going to be equal to, V of 20 is 240, 240, V of 12, we see right there, is 200. And so this is going to be 40 over eight, which is equal to five.