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: a man can do a piece of work in 4 days , but with the help of his son he can do it in 3 days . in what time can the son do it alone ? 
Options: a ) 12 days , b ) 6 days , c ) 5 days , d ) 4 days , e ) none of these

SOLUTION: a

PROBLEM: Problem: a can do a piece of work in 10 days . he works at it for 4 days and then b finishes it in 9 days . in how many days can a and b together finish the work ? 
Options: a ) 6 , b ) 7 , c ) 5 , d ) 4 , e ) 1

SOLUTION: a

PROBLEM: Problem: the rate of spin of a certain gyroscope doubled every 10 seconds from the moment a particular stopwatch started . if after a minute and a half the gyroscope reached a speed of 3200 meters per second , what was the speed , in meters per second , when the stopwatch was started ? 
Options: a ) 25 / 3 , b ) 25 / 4 , c ) 25 / 8 , d ) 25 / 16 , e ) 25 / 32

SOLUTION:
b