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: if a large pizza has a radius that is 10 % larger that that of a medium pizza , what is the percent increase in area between a medium and a large pizza ? 
Options: a ) 15 % , b ) 21 % , c ) 25 % , d ) 30 % , e ) 36 %
b

Problem: a , b and c invested rs . 8000 , rs . 4000 and rs . 8000 respectively in a business . a left after six months . if after eight months , there was a gain of rs . 4005 , then what will be the share of b ? 
Options: a ) rs 690 , b ) rs 790 , c ) rs 890 , d ) rs 990 , e ) none of these
c

Problem: a trader marked the selling price of an article at 50 % above the cost price . at the time of selling , he allows certain discount and suffers a loss of 1 % . he allowed a discount of : 
Options: a ) 7.3 % , b ) 10.5 % , c ) 11 % , d ) 12.5 % , e ) none

a