Correct Answer - Option 4 : 2 hours
Given:
Boy runs a distance of 20 km in 2.5 hrs.
Formula:
Speed = distance/time
Calculations:
Speed = distance/time
speed of boy = 20 kms/(2.5 hrs)
⇒ 8 km/hr
If the speed is doubled the new speed will be = 8 × 2 = 16 km/hr
Then the time taken by the boy to run 32 kms
Time = Distance/speed
time = 32/16
⇒ 2 hours
∴ Required time to run 32 km is 2 hours.