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: what is the compound interest on rs : 40,000 for 4 months at the rate of 5 % per annum 
Options: a ) 670.85 , b ) 671.85 , c ) 672.85 , d ) 673.85 , e ) 674.85
a

Problem: a man can row his boat with the stream at 6 km / h and against the stream in 3 km / h . the man ' s rate is ? 
Options: a ) 1.5 kmph , b ) 3 kmph , c ) 8 kmph , d ) 7 kmph , e ) 5 kmph
a

Problem: find the amount on rs . 5000 in 2 years , the rate of interest being 4 % per first year and 5 % for the second year ? 
Options: a ) 3377 , b ) 2678 , c ) 5460 , d ) 1976 , e ) 1671

c