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: simple interest on a certain sum at a certain annual rate of interest is 1 / 9 of the sum . if the numbers representing rate percent and time in years be equal , then the rate of interest is : 
Options: a ) 5 , b ) 8 , c ) 3 1 / 3 , d ) 2 2 / 3 , e ) none of these
c

Problem: at the end of the month , a certain ocean desalination plant ’ s reservoir contained 26 million gallons of water . this amount is eighth the normal level . if this amount represents 65 % of the reservoir ’ s total capacity , how many million gallons short of total capacity is the normal level ? 
Options: a ) 15 , b ) 25 , c ) 35 , d ) 45 , e ) 55
c

Problem: an investment compounds annually at an interest rate of 34.1 % what is the smallest investment period by which time the investment will more than triple in value ? 
Options: a ) 3 , b ) 4 , c ) 6 , d ) 9 , e ) 12

b