20.The
speed of the boat in still water in 12 kmph. It can travel downstream through
45 kms in 3 hrs. In what time would it cover the same distance upstream?
[A]
3
[C]
6
[B]
5
[D]
3
Answer : [B]
Explanation :
|
|
|
Let
the speed of the current be ‘x’ kmph
|
|
|
|
|
|
Speed
down stream =
|
distance
|
|
|
|
12
+ x = 45 + 3
|
|
|
|
time
|
|
|
|
|
|
|
|
|
|
effective
speed up stream = 12 – 3 = 9
|
|
|
|
|
