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: an error 2 % in excess is made while measuring the side of a square . the percentage of error in the calculated area of the square is : 
Options: a ) 1.04 , b ) 2.04 , c ) 3.04 , d ) 4.04 , e ) none of these
d

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
c

Problem: kanul spent $ 80000 in buying raw materials , $ 30000 in buying machinery and 20 % of the total amount he had as cash with him . what was the total amount ? 
Options: a ) $ 135656 , b ) $ 137500 , c ) $ 134446 , d ) $ 123265 , e ) $ 124564

b