8
Q:
A) 9 kmph | B) 7 kmph |
C) 2 kmph | D) 5 kmph |
Answer: A) 9 kmph
Explanation:
Explanation:
If Mahesh moves 8 km downstream in X hours
Downstream speed = 8/X kmph
upstream speed = 4/X kmph
Now 80/(8/X) + 80/(4/X)=20
X=2/3
downstream Speed = 8/(2/3)= 12 kmph
upstream Speed = 4/(2/3)= 6 kmph
Rate of the stream = (12+6)/2= 9 kmph