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 10 students is 16 years. The age of the 15th student is Choose the correct choice from the following options
A) 9 years B) 11 years C) 14 years D) 21 years E) 9 years

Rationale: "solution age of the 15 th student = [ 15 x 15 - ( 14 x 4 + 16 x 10 ) ] = ( 225 - 216 ) = 9 years . answer e"
Answer: E