Answers

2014-03-08T12:37:46+05:30
Average =  total age/ no. of students
15 = total age/16

total age = 240

new average = (240 - 18)/15
= 222/15
=14.8
2 5 2
2014-03-08T17:58:01+05:30
Average age = total age of all students/no. of students
 15 = t.a s/16
t.a.s = 240
then,after leaving the boy of 18 yrs
t.a.s = 240-18=222
then,av. age of 15( because16-1) students = 222/15
                                                             =14.8
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