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: an escalator moves towards the top level at the rate of 12 ft . sec and its length is 160 feet . if a person walks on the moving escalator at the rate of 8 feet per second towards the top level , how much time does he take to cover the entire length . 
Options: a ) 10 sec , b ) 8 sec , c ) 9 sec , d ) 7 sec , e ) 12 sec
b

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
c

Problem: the s . i . on a certain sum of money for 5 years at 10 % per annum is half the c . i . on rs . 5000 for 2 years at 12 % per annum . the sum placed on s . i . is ? 
Options: a ) 1585 , b ) 1454 , c ) 1656 , d ) 2458 , e ) 1272

e