| A boat covers a certain distance downstream in 1 h, while it comes back in \[1\frac{1}{2}h.\] If the speed of the stream is 3 km/h, then what is the speed of the boat in still water? |
A) 12 km/h
B) 13 km/h
C) 14 km/h
D) 15 km/h
E) None of these
Correct Answer: D
Solution :
| Let the speed of the boat in still water be x km/h. |
| Then, speed downstream \[=(x+3)\,km/h\] |
| and speed upstream \[=(x-3)\,km/h\] |
| \[\therefore \] \[(x+3)\times 1=(x-3)\times \frac{3}{2}\] |
| \[\Rightarrow \] \[2x+6=3x-9\]\[\Rightarrow \]\[x=15\,km/h\] |
You need to login to perform this action.
You will be redirected in
3 sec
