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: joe invested a certain sum of money in a simple interest bond whose value grew to $ 310 at the end of 3 years and to $ 410 at the end of another 5 years . what was the rate of interest in which he invested his sum ?
Options: a ) 6 % , b ) 7 % , c ) 8 % , d ) 9 % , e ) 10 %
[A]: c

[Q]: Problem: a man can row his boat with the stream at 16 km / h and against the stream in 12 km / h . the man ' s rate is ?
Options: a ) 8 kmph , b ) 9 kmph , c ) 2 kmph , d ) 4 kmph , e ) 1 kmph
[A]: c

[Q]: Problem: the amount of principal rs . 8000 at compound interest at the ratio of 5 % p . a . for 2 years is
Options: a ) s . 9621 , b ) s . 6921 , c ) s . 8820 , d ) s . 6261 , e ) s . 6361
[A]:
c