In this task, you need to answer the given multiple-choice question on the physics. Classify your answers into 'a', 'b', 'c', 'd', and 'e'.

Q: Problem: if 20 men can build a wall 112 metres long in 6 days , what length of a similar wall can be built by 30 men in 3 days ? 
Options: a ) 65 mtr . , b ) 84 mtr , c ) 70 mtr . , d ) 78 mtr . , e ) 17 mtr .

A: b
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Q: Problem: express 35 mps in kmph ? 
Options: a ) 122 , b ) 188 , c ) 126 , d ) 140 , e ) 124

A: c
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Q: Problem: how long does a train 165 meters long running at the rate of 72 kmph take to cross a bridge 660 meters in length ? 
Options: a ) 28 , b ) 41.25 , c ) 55 , d ) 18 , e ) 12

A:
b
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