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: a car dealership has 40 cars on the lot , 15 % of which are silver . if the dealership receives a new shipment of 80 cars , 30 % of which are not silver , what percentage of total number of cars are silver ? 
Options: a ) 20 % , b ) 25 % , c ) 30 % , d ) 35 % , e ) 40 %
[EX A]: b

[EX Q]: Problem: a man can row his boat with the stream at 18 km / h and against the stream in 8 km / h . the man ' s rate is ? 
Options: a ) 5 kmph , b ) 2 kmph , c ) 7 kmph , d ) 8 kmph , e ) 3 kmph
[EX A]: a

[EX Q]: Problem: the population of a town is 20000 . it decreases annually at the rate of 20 % p . a . what will be its population after 2 years ? 
Options: a ) 4300 , b ) 4500 , c ) 5120 , d ) 5230 , e ) 12800
[EX A]:
e