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'.

Problem: circular gears p and q start rotating at the same time at constant speeds . gear p makes 10 revolutions per minute and gear q makes 40 revolutions per minute . how many seconds after the gears start rotating will gear q have made exactly 15 more revolutions than gear p ? 
Options: a ) 12 , b ) 15 , c ) 20 , d ) 24 , e ) 30
e

Problem: kathleen can paint a room in 2 hours , and anthony can paint an identical room in 7 hours . how many hours would it take kathleen and anthony to paint both rooms if they work together at their respective rates ? 
Options: a ) 28 / 9 , b ) 4 / 3 , c ) 15 / 8 , d ) 9 / 4 , e ) 15 / 4
a

Problem: p is 30 % more efficient than q . p can complete a work in 23 days . if p and q work together , how much time will it take to complete the same work ? 
Options: a ) 9 , b ) 10 , c ) 11 , d ) 13 , e ) 15

d