The average age of a class of 12 students is 8 yrs. if the teacher's age is also included, the average increases by one year. Find the age of the teacher Choices:
A) 30 Years
B) 31 Years
C) 21 Years
D) 34 Years
E) 49 Years
Total age of students is 12X8 = 96 Years   Total age inclusive of teacher = 13X (8+1) = 117   So, Teacher's age is 117-96= 
<gadget id="calculator">117-96</gadget>
<output>21</output>
21 Yrs   There is a shortcut for these type of problems   Teacher's age is 8+(13X1)= 21 Years   21 Years
<result>C</result>
The average age of a class of 12 students is 8 yrs. if the teacher's age is also included, the average increases by one year. Find the age of the teacher