The boat along the river in 6 hours sailed the same distance that it swims against the current in 9 hours.

The boat along the river in 6 hours sailed the same distance that it swims against the current in 9 hours. How many times the boat’s own speed is greater than the current speed.

Let’s denote the speed of the boat through V1, the speed of the current through V2, and the distance that the boat sailed in one direction through S.

Then the boat swam along the current distance:

S = (V1 + V2) * 6

Against the current, the boat sailed the distance:

S = (V1 – V2) * 9.

Let’s equate both equalities.

(V1 + V2) * 6 = (V1 – V2) * 9.

6 * V1 + 6 * V2 = 9 * V1 – 9 * V2.

3 * V1 = 15 * V2.

V1 = 5 * V2.

Answer: The speed of the boat is 5 times the speed of the current.