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: what is 50 % of 40 % of 1200 grams ? 
Options: a ) 450 gms , b ) 100 gms , c ) 300 gms , d ) 240 gms , e ) none of these

A: d
****
Q: Problem: an error 10 % in excess is made while measuring the side of a square . now what is the percentage of error in the calculated area of the square ? 
Options: a ) 6.64 % , b ) 16.64 % , c ) 15.64 % , d ) 21 % , e ) 10.64 %

A: d
****
Q: Problem: a shopkeeper buys mangoes at the rate of 6 a rupee and sells them at 3 a rupee . find his net profit or loss percent ? 
Options: a ) 33 4 / 3 % , b ) 33 1 / 7 % , c ) 50 % , d ) 32 1 / 3 % , e ) 60 %

A:
c
****