In this task, you need to answer the given multiple-choice question on the general math. Classify your answers into 'a', 'b', 'c', 'd', and 'e'.

[Q]: Problem: the cost to park a car in a certain parking garage is $ 10.00 for up to 2 hours of parking and $ 1.75 for each hour in excess of 2 hours . what is the average ( arithmetic mean ) cost per hour to park a car in the parking garage for 9 hours ? 
Options: a ) $ 1.09 , b ) $ 1.67 , c ) $ 2.225 , d ) $ 2.47 , e ) $ 2.50
[A]: d


[Q]: Problem: a collection of books went on sale , and 2 / 3 of them were sold for $ 2.25 each . if none of the 40 remaining books were sold , what was the total amount received for the books that were sold ? 
Options: a ) $ 160 , b ) $ 150 , c ) $ 280 , d ) $ 200 , e ) $ 180
[A]: e


[Q]: Problem: a mixture contains milk and water in the ratio 5 : 2 . on adding 10 liters of water , the ratio of milk to water becomes 5 : 3 . the quantity of milk in the original mixture is ? 
Options: a ) 30 , b ) 40 , c ) 50 , d ) 60 , e ) 70
[A]:
c