A and B take part in 100 m race. A runs at 5 kmph. A gives B a start of 8 m and still beats him by 8 seconds. The speed of B is:

Correct Answer: 4.14 kmph

A's speed = (5*5/15)m/sec  = (25/18)m/sec

 

Time taken by A to cover 100 m = (100*18/15)sec = 72sec

 

 Time taken by B to cover 92 m = (72 + 8) = 80 sec.

 

 B's speed =(92/80*18/5)kmph =4.14kmph