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: 42 persons can repair a road in 12 days , working 5 hours a day . in how many days will 30 persons , working 6 hours a day , complete the work ? 
Options: a ) 10 , b ) 16 , c ) 13 , d ) 14 , e ) 19

A: d
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Q: Problem: the curved surface of a sphere is 64 π cm 2 . find its radius ? 
Options: ['a ) 8', 'b ) 3', 'c ) 4', 'd ) 9', 'e ) 7']

A: c
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Q: Problem: ajay can walk 4 km in 1 hour . in how many hours he can walk 40 km ? 
Options: a ) 5 hrs , b ) 10 hrs , c ) 15 hrs , d ) 20 hrs , e ) 30 hrs

A:
b
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