## 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)].

## Explanation

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.

## To Find

Speed = ?

## Solution

**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**

Speed = 3.75/0.5

**Speed = 7.5 km/h answer**

## Conclusion

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.