Algebra
posted by Mike .
13. A boat cruises downstream for 2 hours before heading back. It takes 3.5 hours going upstream to get back. If the speed of the stream is 8 mph, what is the speed of the boat in still water?:
a. 14.7 mph
b. 19.6 mph
c. 24.8 mph
d. 29.3 mph

See if you can explain my equation to yourself
3.5(x8) = 2(x+8) then solve it, I got d)