Problem: the average age of 15 students of a class is 15 years . out of these , the average age of 4 students is 14 years and that of the other 9 students is 16 years . tee age of the 15 th student is ? 
Options: a ) 20 years , b ) 22 years , c ) 24 years , d ) 25 years , e ) 27 years
d