Question

A boat travels with the current at a speed of 10 miles per hour with respect to land, then against the same current at a speed of 6 miles per hour with respect to land. Find (a) the speed of the current, and (b) the speed of the boat in still water.

Answer 1

let Vc be the current speed and Vb be the boat speed in still water.

Here is what you know:
Vb + Vc = 10 (downstream speed)
Vb - Vc = 6 (upstream speed)
Adding the two equations gives you
2 Vb = 16
Solve for Vb and then Vc