Question 289377
Let the speed of the boat be x mph in still water

upstream the speed will be x-2 mph

downstream the speed will be x+2

time taken both ways is the same.  ( distance / speed = time)

5/x-2 =7/ x+2

5(x+2)=7(x-2)

5x+10=7x-14

-2x=-24

x=12 mph