Question

A boat takes 6 hours to go downstream and upstream a certain distance. It takes 4 hours to travel twice the distance downstream. Which of the following is the ratio of the speed of the boat in still water to the speed of the river?
Please, help

Answer 1

1) 3:1
2) 1:3
3) 5:3
4) 3:5
5) 7:9

Answer 2

Shortest way, please. Can we use any trick to get the answer in shortest time?

Answer 3

What do you believe the answer is?

Answer 4

I know how to solve it in neat. All I want is the trick!! :)
Here is my logic
let x is the speed of the boat
y is the speed of the water
then the speed of downstream is x +y
upstream is x-y
Let D is distance of the stream, hence
\(\dfrac{D}{x+y}+\dfrac{D}{x-y}=6\\\dfrac{2D}{x+y}=4\)
Solve the system. we can get the answer.