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: car a travels at 3 times the average speed of car b . car a started to travel at 12 : 00 o ' clock , car b started to travel at 16 : 00 o ' clock . what is the speed of car b ( in km / h ) if the total distance that both cars traveled until 18 : 00 was 1000 km ? 
Options: a ) 10 . , b ) 25 . , c ) 30 . , d ) 38 , e ) 50 .
[A]: e


[Q]: Problem: if x / 4 years ago roger was 14 years old and x / 4 years from now he will be 4 x years old , how old will he be 6 x years from now ? 
Options: a ) 32 , b ) 39 , c ) 30 , d ) 40 , e ) 28
[A]: b


[Q]: Problem: on day one , a store sold 96 pens . on each of the next d days , the company sold 44 pens . if the average daily sales of pens over this time period ( including day one ) is 48 pens , what is the value of d ? 
Options: a ) 9 , b ) 10 , c ) 11 , d ) 12 , e ) 13
[A]:
d