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: gold is 19 times as heavy as water and copper is 9 times as heavy as water . in what ratio should these be mixed to get an alloy 15 times as heavy as water ? 
Options: a ) 3 : 2 , b ) 3 : 8 , c ) 5 : 7 , d ) 3 : 7 , e ) 3 : 6

A: a
****
Q: Problem: two trains of equal length are running on parallel lines in the same directions at 46 km / hr . and 36 km / hr . the faster trains pass the slower train in 144 seconds . the length of each train is : 
Options: a ) 82 m , b ) 150 m , c ) 172 m , d ) 200 m , e ) none of these

A: d
****
Q: Problem: if the number 992 , 132,24 x is divisible by 11 , what must be the value of x ? 
Options: a ) 1 , b ) 2 , c ) 3 , d ) 4 , e ) 0

A:
e
****