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: a and b can do a work in 12 days , b and c in 15 days , c and a in 20 days . if a , b and c work together , they will complete the work in : 
Options: a ) 5 days , b ) 7 5 / 6 days , c ) 10 days , d ) 15 2 / 3 days , e ) none of these

A: c
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Q: Problem: the speed at which a man can row a boat in still water is 15 km / hr . if he rows downstream , where the speed of current is 3 km / hr , how many seconds will he take to cover 90 meters ? 
Options: a ) 12 , b ) 16 , c ) 17 , d ) 18 , e ) 20

A: d
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Q: Problem: stacy has a 63 page history paper due in 3 days . how many pages per day would she have to write to finish on time ? 
Options: a ) 9 , b ) 8 , c ) 10 , d ) 8.5 , e ) 21

A:
e
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