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: if the radius of a cylinder is doubled and height 5 times , what is the new volume of the cylinder divided by the old one ? 
Options: a ) 8 . , b ) 2 . , c ) 6 . , d ) 20 . , e ) 10 .
[EX A]: d

[EX Q]: Problem: how many paying stones , each measuring 2 1 / 2 m * 2 m are required to pave a rectangular court yard 20 m long and 16 1 / 2 m board ? 
Options: a ) 66 , b ) 18 , c ) 16 , d ) 10 , e ) 15
[EX A]: a

[EX Q]: Problem: the sum of the present ages of two persons a and b is 60 . if the age of a is twice that of b , find the sum of their ages 10 years hence ? 
Options: a ) 58 , b ) 59 , c ) 62 , d ) 70 , e ) 80
[EX A]:
e