# 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. How Fast did He Run?

## 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).
1. Time will be changed to hours.
2.  Distance covered in first 45 minutes by Mr Khawaja will be find out using distance – speed formula.
3. Distance of running will be figured out.
4. Speed of Mr Khawaja in half an hour would be determined using distance – speed formula.

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

## 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.