The average age of 30 boys of a class is equal to 14 yrs. When the age of the class teacher is included the average becomes 15 yrs. Find the age of the class teacher.
Choose the correct option:
A) 40 yrs
B) 42 yrs
C) 45 yrs
D) 46 yrs
E) 47 yrs
The average age of 30 boys of a class is equal to 14 yrs:   i.e Sum of all boys:30*14   include class teacher:31 candidates in a class   &amp; avg age is:15 yr   i.e. sum of all:31*15(include class teacher)=465   so,the age of the class teacher:  465-420= 
<gadget id="calculator">  465-420</gadget>
<output>45</output>
45yr   answer will be 45 yrs   ANSWER:45 yrs
<result>C</result>
The average age of 30 boys of a class is equal to 14 yrs. When the age of the class teacher is included the average becomes 15 yrs. Find the age of the class teacher.