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: how many numbers from 19 to 79 are exactly divisible by 11 ? 
Options: a ) 5 , b ) 6 , c ) 9 , d ) 11 , e ) 12
[A]: b


[Q]: Problem: cost is expressed by the formula tb ^ 4 . if b is doubled , the new cost is what percent of the original cost ? 
Options: a ) 200 , b ) 600 , c ) 800 , d ) 1600 , e ) 50
[A]: d


[Q]: Problem: if x / y = 8 / 7 , then ( 7 x + 6 y ) / ( 7 x â € “ 6 y ) = ? 
Options: a ) 11 , b ) 8 , c ) 9 , d ) 7 , e ) 6
[A]:
d