TASK DEFINITION: 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'.
PROBLEM: Problem: a family made a down payment of $ 300 and borrowed the balance on a set of encyclopedias that cost $ 750 . the balance with interest was paid in 9 monthly payments of $ 57 each and a final payment of $ 21 . the amount of interest paid was what percent of the amount borrowed ? 
Options: a ) 6 % , b ) 12 % , c ) 14 % , d ) 18.66 % , e ) 20 %

SOLUTION: d

PROBLEM: Problem: a fellow borrowed a certain sum of money at 5 % per annum at simple interest and in 5 years the interest amounted to rs . 2250 less than the sum lent . what was the sum lent ? 
Options: a ) 1050 , b ) 1220 , c ) 1250 , d ) 1060 , e ) 3000

SOLUTION: e

PROBLEM: Problem: what is the rate percent when the simple interest on rs . 600 amount to rs . 160 in 4 years ? 
Options: a ) 6.66 % , b ) 7.66 % , c ) 6.06 % , d ) 6.16 % , e ) 8.66 %

SOLUTION:
a