Mr Khawaja walked for 45 minutes at the rate of 3km/h.
- He then ran for half an hour at a certain speed.
- At the end of that time he was 6km away from the starting point.
- The speed of Mr Khawaja can be figure out in this way.
Note: This question was asked in Competitive Examination (CSS) – 2021 General Science & Ability under Section – B [Q. 6. (d)].
Following things are needed to discuss here.
- Distance covered by Mr Khawaja in first 45 minutes.
- Distance he travelled during running.
- Speed of Mr Khawaja.
Following things are given.
- Initial time of walk (45 minutes).
- Initial speed (3 km/h).
- Total distance (6 km).
- Time will be changed to hours.
- Distance covered in first 45 minutes by Mr Khawaja will be find out using distance – speed formula.
- Distance of running will be figured out.
- Speed of Mr Khawaja in half an hour would be determined using distance – speed formula.
Speed = ?
Conversion of unit
Walking time = 45 minutes = 45/60 = 0.75 hours
Distance covered in first 45 minutes
Speed = 3 km/h (given)
As, we know that
Speed = distance / time
Distance = speed x time
Distance = 3 x 0.75
Distance = 2.25 km
Distance of running
Total distance = 6 km
Distance covered by running = 6 – 2.25 km = 3.75 km
Running time = 0.5 hour (given)
Speed = 3.75/0.5
Speed = 7.5 km/h answer
Mr Khawaja walked for 45 minutes at the rate of 3km/h and then ran for half an hour at a certain speed. At the end of that time he was 6km away from the starting point. He ran at 7.5 km/h.