In this task, you need to provide the correct option for a given problem from the provided options.

Problem: the ratio of the arithmetic mean of two numbers to one of the numbers is 5 : 8 . what is the ratio of the smaller number to the larger number ? 
Options: a ) 1 : 8 , b ) 1 : 6 , c ) 1 : 5 , d ) 1 : 4 , e ) 1 : 3
d

Problem: income and expenditure of a person are in the ratio 5 : 4 . if the income of the person is rs . 17000 , then find his savings ? 
Options: a ) 3600 , b ) 3400 , c ) 3608 , d ) 3602 , e ) 3603
b

Problem: if 35 % of the 880 students at a certain college are enrolled in biology classes , how many students at the college are not enrolled in a biology class ? 
Options: a ) 110 , b ) 330 , c ) 572 , d ) 430 , e ) 880

c