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: in a renowned city , the average birth rate is 6 people every two seconds and the death rate is 3 people every two seconds . estimate the size of the population net increase that occurs in one day .
Options: a ) 129,500 , b ) 129,600 , c ) 129,700 , d ) 129,800 , e ) 129,900
[EX A]: b

[EX 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
[EX A]: b

[EX Q]: Problem: if 5 x = 6 y and xy = 0 , what is the ratio of 1 / 3 * x to 1 / 5 * y ?
Options: a ) 25 / 6 , b ) 36 / 25 , c ) 2 , d ) 5 / 6 , e ) 25 / 36
[EX A]:
c