We have 20 chances out of 100 which is 20/100=1/5 other known as 1 in 5 chance
The even numbers are 2, 4, 6, .., 100. 50 chances out of 100 which is 50/100=1/2 other know as 1 in 2 chance
(-2)(-5)(-7)
(10)(-7)
-70
The product is -70
V=(4/3)pir^3
r=3
V=(4/3)pi3^3
V=36pi
v=113.04 cubic feet