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'.

[EX Q]: Problem: working simultaneously and independently at an identical constant rate , 5 machines of a certain type can produce a total of x units of product p in 4 days . how many of these machines , working simultaneously and independently at this constant rate , can produce a total of 2 x units of product p in 2 days ? 
Options: a ) 11 , b ) 13 , c ) 15 , d ) 18 , e ) 20
[EX A]: e

[EX Q]: Problem: if x ^ 2 + y ^ 2 = 15 and xy = 3 , then ( x − y ) ^ 2 = 
Options: a ) 8 , b ) 9 , c ) 14 , d ) 17 , e ) 20
[EX A]: b

[EX Q]: Problem: every year an amount increases by 1 / 8 th of itself . how much will it be after two years if its present value is rs . 59000 ? 
Options: a ) 81000 , b ) 81007 , c ) 74671.875 , d ) 81066 , e ) 81022
[EX A]:
c