The average age of 40 students is 8 years. If the age of teacher is also included , then their average age increases by half a year. What is the age of the teacher?
Choose the correct choice from the following choices.
A) 45 years	B) 48.5 years	C) 28.5 years	D) 26.5 years	E) 27.5 years
Total age of 40 students = 40*8= 
<gadget id="calculator">40*8</gadget>
<output>320</output>
320   Let the age of the the teacher be x, Then (320+x)/41= 8+1/2 =8 ½.   320+x =17/2*41 =697/2= 
<gadget id="calculator">697/2</gadget>
<output>697/2 = around 348.5</output>
348.5,   x=348.5-320= 
<gadget id="calculator">348.5-320</gadget>
<output>28.5</output>
28.5   ANSWER:28.5 years
<result>C</result>
The average age of 40 students is 8 years. If the age of teacher is also included , then their average age increases by half a year. What is the age of the teacher?