In this task, you need to answer the given multiple-choice question on the gain. Gain is the value by which to multiply the input. Classify your answers into 'a', 'b', 'c', 'd', and 'e'.
Q: Problem: if you spend 1 / 4 of your salary during the first week of the month and 20 % of it during each of the coming 3 weeks , what part ( fraction ) of your salary will leave unspent at the end of the month ?
Options: a ) 2 / 20 , b ) 3 / 20 , c ) 4 / 20 , d ) 5 / 20 , e ) none
A:
b