11. A boat takes 19 hours for travelling
downstream from point A to point B and coming back to a point C midway between
A and B. If the velocity of the stream is 4 kmph and the speed of the boat in
still water is 14 kmph, what is the distance between A and B ?
A. 160
km B.
180 km
C. 200 km D. 220 km
Answer:
|
Speed
Downstream
|
=
(14 + 4) km/hr
|
|
= 18
km/hr.
|
|
Speed
upstream
|
=(14
- 4) km/hr
|
|
= 10
km/hr..
|
|
Let
the distance b/w A and B
be xkm.Then
|
=(x/18+
x/2 / 10)
|
|
= 19
|
|
=
19x / 180 = 19
|
|
x=
180.
|
