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'.
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Question: Problem: a customer bought a product at the shop . however , the shopkeeper increased the price of the product by 10 % so that the customer could not buy the required amount of the product . the customer managed to buy only 80 % of the required amount . what is the difference in the amount of money that the customer paid for the second purchase compared to the first purchase ? 
Options: a ) 10 % , b ) 12 % , c ) 14 % , d ) 16 % , e ) 18 %

Answer: b


Question: Problem: the average age of a group of 10 persons was decreased by 3 years when one person , whose age was 42 years , was replaced by a new person . find the age of the new person ? 
Options: a ) 22 , b ) 18 , c ) 12 , d ) 88 , e ) 66

Answer: c


Question: Problem: what is the units digit of ( 7 ! * 6 ! + 6 ! * 4 ! ) / 2 ? 
Options: a ) 0 , b ) 1 , c ) 2 , d ) 3 , e ) 4

Answer:
a