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 money lender lent rs . 1000 at 4 % per year and rs . 1400 at 5 % per year . the amount should be returned to him when the total interest comes to rs . 350 . find the number of years . 
Options: a ) 3.2 , b ) 3.75 , c ) 4 , d ) 4.25 , e ) 4.5
a

Problem: a , b and c invested rs . 6300 , rs . 4200 and rs . 10500 respectively , in a partnership business . find the share of a in profit of rs . 12400 after a year ? 
Options: a ) 3630 , b ) 2881 , c ) 3720 , d ) 9977 , e ) 2212
c

Problem: on a sum of money , the simple interest for 2 years is rs . 660 , while the compound interest is rs . 696.30 , the rate of interest being the same in both the cases . the rate of interest is : 
Options: a ) 10 % , b ) 10.5 % , c ) 12 % , d ) none of these , e ) can not be determined

d