What = 6 x y = 72? 12! X=12 in!!
Volume 72+72= Your answer!! (144) I think! :D

The answer is the third option, -7.
Hope this helps.
A tenth is 1/10.
5 tenths is 5/10.
5/10 is a fraction that can be made simpler, by dividing by 5, so that the fraction becomes 1/2.
1/2 is a half, so if you have a half a dollar, you have 50 cents.
Hope I helped. :)