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: find the c . i . on a sum of rs . 10000 for 6 months at 20 % per annum , interest being compounded halfyearly ? 
Options: a ) 3010 , b ) 2010 , c ) 1000 , d ) 3100 , e ) 2100

A: c
****
Q: Problem: if the cost price of 50 articles is equal to the selling price of 15 articles , then the gain or loss percent is ? 
Options: a ) 16 , b ) 127 , c ) 12 , d ) 18 , e ) 233

A: e
****
Q: Problem: in a public show 45 % of the seats were filled . if there were 600 seats in the hall , how many seats were vacant ? 
Options: a ) 330 , b ) 110 , c ) 120 , d ) 140 , e ) 150

A:
a
****