The average age of a group of 10 friends is 15 yr. If one friend leaves the group, the average becomes 16 yr. Find the age of the friend who left the group.	Select the correct option:  A) 5 yr  B) 4 yr  C) 6 yr  D) None of these  E) Cannot be determined
Answer   Age of friend left = Previous average of the age - Number of persons present x Increase in average age   = 15 - ( 10-1 ) x ( 16-15 )   = 15- 9 x 1   = 15 - 9= 
<gadget id="calculator">15 - 9</gadget>
<output>6</output>
6yr   6 yrorrect Option: 6 yr
<result>C</result>
The average age of a group of 10 friends is 15 yr. If one friend leaves the group, the average becomes 16 yr. Find the age of the friend who left the group.