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DS Prob from Qant aptitude book by TATA McGraw Hill

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by amitansu » Tue May 06, 2008 8:51 pm
Who is the fastest among the three workers - P,Q and R ?

1. P & Q together fence a garden(of perimeter 800m) in 19 hrs.

2. P,Q and R together fence a garden (of perimeter 800m) in 9 hrs.
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Source: — Data Sufficiency |

by Neo2000 » Tue May 06, 2008 10:43 pm
Combining both statements you can find some value for the speed of R. This has to be less than 19 since we know how much time P+Q take and we know that P+Q+R is less than 19 i.e. 9hours.

Let's assume that Q did no work, then at the very least P takes 19hrs to finish the wall all by himself. If P's speed was less than R then time taken for P+Q would be a lot less than 19. So P is slower than R. Even Q is slower than R

Hence R is the fastest.
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