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'.

[EX Q]: Problem: if the simple interest on a certain amount in at 4 % rate 5 years amounted to rs . 2080 less than the principal . what was the principal ? 
Options: a ) 1500 , b ) 2600 , c ) 2507 , d ) 3200 , e ) 11500
[EX A]: b

[EX Q]: Problem: tickets to a certain concert sell for $ 20 each . the first 10 people to show up at the ticket booth received a 40 % discount , and the next 20 received a 15 % discount . if 50 people bought tickets to the concert , what was the total revenue from ticket sales ? 
Options: a ) $ 600 , b ) $ 740 , c ) $ 860 , d ) $ 980 , e ) $ 1,140
[EX A]: c

[EX Q]: Problem: $ 20000 will become $ 60000 at 20 % p . a . find the time ? 
Options: a ) 2 years , b ) 5 years , c ) 7 years , d ) 8 years , e ) 10 years
[EX A]:
e