The task is to generate the correct answer for a given math problem.

[EX Q]: Problem: if a drawing has an outer circle of diameter 30 and an inner circle of diameter 24 , then what fraction of outer circle ' s surface is not covered by the inner circle ?
[EX A]: 9 / 25', 'e ) 2 / 3'

[EX Q]: Problem: 5 / 8 of 3 / 10 of a number is greater than 4 / 9 of 1 / 4 of the same number by 55 . what is half of that number ?
[EX A]: 36

[EX Q]: Problem: a cube of edge 16 cm is immersed completely in a rectangular vessel containing water . if the dimensions of the base of vessel are 20 cm * 15 cm , find the rise in water level ?
[EX A]:
13.65 cm