Rahul runs at a speed of 6 km/h in a 100-metre race. Rahul gives Bharat a start of 4 metres and still beats him by 4 seconds. Find Bharat’s speed.
- A5.8 km/h
- B4.5 km/h
- C4.9 km/h
- D5.4 km/h
Solution & Step-by-step Explanation
Rahul's speed = 6 km/h=6×
18
5
=
3
5
m/s.
Time taken by Rahul to complete the 100 m race:
t
Rahul
=
3
5
100
=100×
5
3
=60 seconds
Rahul gives Bharat a start of 4 m, so Bharat only needs to run:
Distance
Bharat
=100−4=96 m
Rahul beats Bharat by 4 seconds, meaning Bharat takes 4 seconds longer than Rahul:
t
Bharat
=60+4=64 seconds
Bharat's speed:
Speed
Bharat
=
64
96
=1.5 m/s
Convert Bharat's speed to km/h:
Speed
Bharat
=1.5×
5
18
=5.4 km/h
18
5
=
3
5
m/s.
Time taken by Rahul to complete the 100 m race:
t
Rahul
=
3
5
100
=100×
5
3
=60 seconds
Rahul gives Bharat a start of 4 m, so Bharat only needs to run:
Distance
Bharat
=100−4=96 m
Rahul beats Bharat by 4 seconds, meaning Bharat takes 4 seconds longer than Rahul:
t
Bharat
=60+4=64 seconds
Bharat's speed:
Speed
Bharat
=
64
96
=1.5 m/s
Convert Bharat's speed to km/h:
Speed
Bharat
=1.5×
5
18
=5.4 km/h