24 total balls. 17 Not red, so 24-17=7. 7 Red balls. That leaves 17 balls. 10 of them are neither yellow nor blue, and since the amount of red balls has been figured out, we do not need to account for them. 17 balls - 10 not yellow or blue equals 7 balls that can be yellow or blue. 17 balls left, minus the 7 yellow or blue balls equals 10.
