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'.
One example is below.
Q: Problem: walking at 5 / 6 th of its usual speed a cab is 15 mnts late . find its usual time to cover the journey ? 
Options: a ) 25 m , b ) 45 m , c ) 32 m , d ) 75 m , e ) 62 m
A: d
Rationale: New speed = 5 / 6 th of usual speed new time = 6 / 5 th of usual time 6 / 5 ut - ut = 15 m ut / 5 = 15 m ut = 75 m answer is d
Q: Problem: a is 1.5 times as fast as b . a alone can do the work in 30 days . if a and b working together in how many days will the work be completed ? 
Options: a ) 23 , b ) 18 , c ) 21 , d ) 24 , e ) 25
A:
b