.875 seconds
a=360t
b=280t+(280*.25)
360t=280t+(280*.25)
360t=280t+70
80t=70
t=.875
V=hpir²
h=8
d=2r
d/2=r
5/2=2.5=r
V=8pi2.5²
V=8pi6.25
V=50pi
aprox pi=3.14
V=50 times 3.14
V=157 in³
157 cubic inches
Show more of the pic because I cant see the options for what to choose.