Time, Speed & Distance
Aptitude

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Q.

A boat goes 30 km. upstream and 44 km. downstream in 10 hours. In 13 hours, it can go 40 km upstream and 55 km down-stream. The speed of the boat in still water is:

 A.

3 km/hr

 B.

4 km/hr

 C.

8 km/hr

 D.

6 km/hr

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Solution:
Option(C) is correct

If $B$ = speed of boat in still water

$R$ = speed of stream

Then as per the question:

\(\dfrac{30}{(B-R)}+\dfrac{44}{(B-R)}=10\)---------(i)

\(\dfrac{40}{(B-R)}+\dfrac{55}{(B-R)}=13\)---------(ii)

On solving both the equations we get: $B$ = 8 km/hr


(2) Comment(s)


Nitu
 ()

There is an error in answer It should be B+R while taking upstream.


Nitu
 ()

Sorry its downstream