Race

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Race

by gmatv09 » Fri Aug 21, 2009 2:10 pm
A and B ran a race of 480 m. In the first heat, A gives B a head start of 48 m and beats him by 1/10th of a minute. In the second heat, A gives B a head start
of 144 m and is beaten by 1/30th of a minute. What is B's speed in m/s?

(A) 12
(B) 14
(C) 16
(D) 18
(E) 20
Source: — Problem Solving |

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by pandeyvineet24 » Fri Aug 21, 2009 2:40 pm
Its 12

from 1st situation.

(480-48)/Rb - 480/Ra = 6

2nd Situation

480/Ra - (480-144)/Rb = 2

add the 2 equations

gives Rb = 12.

I messed it up myself in the calculation and took well over 3 mins. :(