Question

two friends went rowing on the river. they traveled with current for 3 hours. the way back took them 4 hours and 48 minutes. find the speed of the rivers current if they can row in still water at the speed of 6.5 mph

Answer 1

1.5 mph

Explanation:

The speed in the still water = 6.5 mph.

The speed of the current = x mph.

1. Two friends traveled with current for 3 hours. The speed with the current is 6.5 + x mph, so they traveled
`3(x+6.5)` miles.

2. Two friends traveled against the current for 4 hours and 48 minutes that is
`4(4)/(5)=4.8` hours. The speed against the current is 6.5 - x mph, so they traveled
`4.8(6.5-x)` miles.

They traveled the same distance with the current and against the current, hence,

`3(x+6.5)=4.8(6.5-x)`

Solve this equation:

`3x+19.5=31.2-4.8x\\ \\3x+4.8x=31.2-19.5\\ \\7.8x=11.7\\ \\x=1.5\ mph`