algebra
posted by maggie .
A tugboat goes 180 miles upstream in 15 hours. The return trip downstream takes 10 hours. find the speed of the tugboat without a current and the speed of the current

distance=(velocityboat+vstream)time
180=(vb+Vs)*10
180=(VbVs)*15
divide both sides of a) by 10, and b) by 15
18=vb+vs
12=VbVs
add the equations
30=2vb solve for vboat
then put that into either equation and solve for vstream