A fisherman traveled in a boat from point N upstream. After having traveled 6 km, he stopped rowing and 2 hour 40 min after first leaving N, he was brought back to N by the current. Knowing that the speed of the boat in still water is 9 km/hour, find the speed of the river’s current.

Answer 1

t = d / r

[6 / (9 - c)] + [6 / (9 + c)] = 8/3 hr

6(9 + c) + 6(9 - c) = 8/3(81 - c^2)

108 = 216 - (8/3 c^2) ... 0 = 108 -(8/3 c^2)

use quadratic formula to find c

Answer 2

Thx!

Answer 3

But, so is c the speed