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?  Choose the correct option:	A) 11	B) 19	C) 12	D) 17	E) 14
Initial average age of the 10 persons be P.   Age of the new person Q.   Sum of the ages of the initial 10 persons = 10P   New average = (P-3) 10(P-3) = 10P - 42 + Q =&gt; Q   = 12   Answer: 12
<result>C</result>
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?