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: a shopkeeper has 100 kg of apples . he sells 50 % of these at 25 % profit and remaining 50 % at 30 % profit . find his % profit on total . 
Options: a ) 27.5 % , b ) 25.6 % , c ) 31.5 % , d ) 35.9 % , e ) 29.5 %
a

Problem: the present worth of rs . 2310 due years hence , the rate of interest being 15 % per annum , is : 
Options: a ) rs . 1440 , b ) rs . 1750 , c ) rs . 1680 , d ) rs . 1840 , e ) none of these
c

Problem: there are 300 seniors at morse high school , and 40 % of them have cars . of the remaining grades ( freshmen , sophomores , and juniors ) , only 10 % of them have cars . if 15 % of all the students at morse have cars , how many students are in those other 3 lower grades ? 
Options: a ) 600 , b ) 900 , c ) 1200 , d ) 1350 , e ) 1500

e