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: 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

A: a
****
Q: Problem: ? % of 360 = 108.0 
Options: a ) 277 , b ) 36 , c ) 64 , d ) 72 , e ) 30

A: e
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Q: Problem: find the simple interest on $ 10000 at 9 % per annum for 12 months ? 
Options: a ) $ 410 , b ) $ 500 , c ) $ 650 , d ) $ 710 , e ) $ 900

A:
e
****