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: how is 4 % expressed as a decimal fraction ? 
Options: a ) 0.4 , b ) 0.04 , c ) 0.004 , d ) 0.0004 , e ) 4
b

Problem: a milk man has 20 liters of milk . if he mixes 25 liters of water , which is freely available , in 20 liters of pure milk . if the cost of pure milk is rs . 18 per liter , then the profit of the milkman , when he sells all the mixture at cost price is : 
Options: a ) 20 % , b ) 45 % , c ) 33.33 % , d ) 18 % , e ) none of these
b

Problem: the price of a book is increased from $ 300 to $ 330 . what is the % of increase in its price ? 
Options: a ) 10 % , b ) 20 % , c ) 30 % , d ) 35 % , e ) 45 %

a