A can run 1 km in 3 min. 10 sec. and B can cover the same distance in 3 min. 20 sec. By what distance can A beat B ? Choose the correct choice from the following choices.
A) 30 metres B) 50 metres C) 48 metres D) 55 metres E) 20 metres
Clearly, A beats B by 10 sec.   Distance covered by B in 10 sec. = ((1000/200) x 10 )m = 50 m.   Therefore A beats B by 50 metres.   Answer is 50 metres.
<result>B</result>
A can run 1 km in 3 min. 10 sec. and B can cover the same distance in 3 min. 20 sec. By what distance can A beat B ?