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

[Q]: Problem: find ( 7 x + 2 y ) / ( x - 2 y ) if x / 2 y = 3 / 2 ?
[A]: 23


[Q]: Problem: how many prime numbers are between 51 / 13 and 89 / 9 ?
[A]: 2


[Q]: Problem: in the number 10,0 ab , a and b represent the tens and units digits , respectively . if 11,0 ab is divisible by 55 , what is the greatest possible value of b × a ?
[A]:
15