TASK DEFINITION: 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: Problem: twelve machines , each working at the same constant rate , together can complete a certain job in 6 days . how many additional machines , each working at the same constant rate , will be needed to complete the job in 3 days ? 
Options: a ) 14 , b ) 12 , c ) 15 , d ) 16 , e ) 18

SOLUTION: b

PROBLEM: Problem: walking with 4 / 5 of my usual speed , i arrive at the bus stop 7 minutes later than normal . how many minutes does it take to walk to the bus stop at my usual speed ? 
Options: a ) 12 , b ) 16 , c ) 20 , d ) 24 , e ) 28

SOLUTION: e

PROBLEM: Problem: bruce and anne can clean their house in 4 hours working together at their respective constant rates . if anne ’ s speed were doubled , they could clean their house in 3 hours working at their respective rates . how many hours does it currently take anne to clean the house on her own ? 
Options: a ) 6 , b ) 7 , c ) 8 , d ) 12 , e ) 14

SOLUTION:
d