In this task, you need to answer the given multiple-choice question on the general math. Classify your answers into 'a', 'b', 'c', 'd', and 'e'.

[Q]: Problem: if 5 x = 6 y and xy ≠ 0 , what is the ratio of 1 / 3 * x to 1 / 5 * y ? 
Options: a ) 25 / 6 , b ) 36 / 25 , c ) 2 , d ) 5 / 6 , e ) 25 / 36
[A]: c


[Q]: Problem: how many multiples of 2 are there between 10 and 52 , 10 and 52 inclusive ? 
Options: a ) 27 , b ) 25 , c ) 24 , d ) 21 , e ) 22
[A]: e


[Q]: Problem: find the value of ( 20 c 18 ) * ( 20 c 20 ) 
Options: a ) 400 , b ) 380 , c ) 360 , d ) 350 , e ) 330
[A]:
b