A man has to cover a distance of 32 km. After 1 hour 20 minutes he noticed that the distance he covered is 5/7 of the remaining distance. What was his speed in km/hr?

Correct option is D

Concept Used:-
Time = Distance / Speed
Solution:
Total distance = 32 km.
Distance covered in 1 hour 20 minutes = 5/7 of the remaining distance.
Suppose, the speed of the man = x km/hr.
So, the distance is covered in 1 hour and 20 minutes.
=> Distance = (x) × (1 + 20/60) (∵ 1 min = 1/60 hr)
=> Distance = (x) × (1 + 1/3)  = (4x/3)
Now, according to the questions,
Distance covered in 1 hour 20 minutes = 5/7 of the remaining distance.
=> 4x/3 = (5/7) × {32- (4x/3)}
=> 28x/15 = 32 - (4x)/3
=> x = 10 km/hr
So, the speed of the man is 10 km/hr.