Quantitative Aptitude Ques 676
Question: A streamer goes downstream from one port to another in 4 h. It covers the same distance upstream in 5 h. If the speed of stream is 2 km/h, then the distance between the two ports is
Options:
A) 50 km
B) 60 km
C) 70 km
D) 80 km
Show Answer
Answer:
Correct Answer: D
Solution:
- Let the distance between two ports be $ xkm. $ Let the speed of streamer in still water $ =ykm/h $
$ \therefore $ $ \frac{x}{y+2}=4 $
(i)
and $ \frac{x}{y-2}=5 $
(ii)
From Eqs. (i) and (ii), we get
$ 4,(y+2)=5,(y-2) $
$ \Rightarrow $ $ 4y+8=5y-10 $
$ \Rightarrow $ $ 5y-4y=10+8 $
$ \Rightarrow $ $ y=18\text{km/h} $
From Eq. (i), we get
$ \frac{x}{18+2}=4 $
$ \Rightarrow $ $ x=4\times 20=80km $
BETA
