problem solving mathematics

Question

A boat can row downstream, travels 120 miles in 2 hours. The return trip upstream takes 2.5 hours. Find the speed of the boat and the current.

Answer 1

120 = 2(b+c)

60=b+c

120 = 2.5(b-c)

120/2.5 = b-c

48=b-c

12 = 2c

c = 6 mph = current speed

b =60-6 = 54 mph = boat speed

2b+2c = 120

2.5b -2.5c = 120

5b +5c = 300

5b -5c = 240

10c = 60

c = 6 mph= current speed

b=60-c = 54 mph = boat speed