Answer: 16
If 5/8 of a number, let's call it x, is 40, we can set up the following equation:
5/8 * x = 40
Dividing both sides by 5/8, we get x = 64
Now that we know that the number is 64, we can find a quarter of it by multiplying by 1/4 as follows:
64 * (1/4) = 16