The average age of 12 students is 20 years. If the age of one more student is included, the average decreases by 1, what is the age of the new student?  Choose the correct option:
A) 5	B) 7	C) 9	D) 11	E) 13
Average age of 12 students is 20 years means sum of 12 students age is 240   If the age of one more student is included, the average decreases by 1, means 13 students age is   13*19= 
<gadget id="calculator">  13*19</gadget>
<output>247</output>
247   Difference between 12 and 13 students is 7.   ANSWER:7
<result>B</result>
The average age of 12 students is 20 years. If the age of one more student is included, the average decreases by 1, what is the age of the new student?