This is a combination in which you choose 4 from 10.
The formula is
combinations = 10! / 4! * (10-4)!
combinations = 10! / 4! * 6!
combinations = 10 * 9 * 8 * 7 * 6! / 4! * 6!
combinations = 10 * 9 * 8 * 7 / 4 * 3 * 2
combinations = 10 * 3 * 7
combinations = 210
Source:
http://www.1728.org/combinat.htm
4 classes, $52
Do it the long way to check
Find the volume of the cone Vc
Find volume of sphere Vs
Volume of shaded figure Vsh=Vc-Vs
Umm I didn't get a domain.... No solutions were found...