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 sum of money for 4 years at 8 % per annum is rs . 560 , what is the compound interest on the same sum at the rate and for the same time ? 
Options: a ) rs . 640.86 , b ) rs . 430.86 , c ) rs . 330.86 , d ) rs . 630.86 , e ) rs . 130.86
[EX A]: d

[EX Q]: Problem: a man walking at a rate of 15 km / hr crosses a bridge in 10 minutes . the length of the bridge is ? 
Options: a ) 500 m , b ) 1110 m , c ) 950 m , d ) 1000 m , e ) 1300 m
[EX A]: a

[EX Q]: Problem: mixture a is 20 percent alcohol , and mixture b is 50 percent alcohol . if the two are poured together to create a 15 gallon mixture that contains 30 percent alcohol , approximately how many gallons of mixture a are in the mixture ? 
Options: a ) 3 gallons , b ) 4 gallons , c ) 5 gallons , d ) 10 gallons , e ) 12 gallons
[EX A]:
d