The average age of a class of 39 students is 15 years. If the age of the teacher be included, then the average increases by3 months. Find the age of the teacher.	Choose the correct choice from the following answers:
A) 25 years B) 16 years C) 8 years D) 6 years E) 12 years
Sol. Total age of 39 persons = (39 x 15) years   = 585 years.   Average age of 40 persons= 15 yrs 3 months   = 61/4 years.   Total age of 40 persons = (_(61/4 )x 40) years= 610 years.   :. 25 yearsge of the teacher = (610 - 585)= 
<gadget id="calculator">(610 - 585)</gadget>
<output>25</output>
25 years   25 yearsns: 25 years
<result>A</result>
The average age of a class of 39 students is 15 years. If the age of the teacher be included, then the average increases by3 months. Find the age of the teacher.