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.