Find the rate of the current and the rate of the boat in still water.

Question

a motorboat travels 64 miles in 2 hours going upstream. it travels 84 miles going downstream in same amount of time. What is the rate of the boat in still water and what is the rate of the current?

Answer 1

R is the speed of the boat

S is the speed of the current

downstream, 84 miles in 2 hours

84 = (r+s)*2

42 = r+s

upstream: 64 miles in 2 hours

64 = (r-s)*2

32 = r-s

adding these two results:

74 = 2r

r=37

which forces s=5

the speed of the boat is 37

the speed of the current is 5.