A and B compete in a 100-meter dash. A travels at a speed of 5 kilometres per hour. A starts 8 metres ahead of B and yet defeats him by 8 seconds. B moves at the following rate:
A. 5.15 kmph
B. 4.14 kmph
C. 4.25 kmph
D. 4.4 kmph
Answer:B
A and B compete in a 100-meter dash. A travels at a speed of 5 kilometres per hour. A starts 8 metres ahead of B and yet defeats him by 8 seconds. B moves at the following rate:
A. 5.15 kmph B. 4.14 kmph C. 4.25 kmph D. 4.4 kmph
Explanation: 5 × 5/18 m/sec = 25/18 m/sec is A's speed.A's time to cover 100 metres is 100/25 x 18 seconds, or 72 seconds.B's time to cover 92 metres is (72 + 8) = 80 seconds.B's speed is equal to 92/80 x 18/5 kmph = 4.14 kmph.