The average age of 15 students of a class is 15 years. Out of these the average age of 5 students is 14 years and that of the other 9 students is 16 years. The age of the 15th student is:
Answer & explanation
Correct answer: option 1
Total age of 15 students = (15×15)years = 225years
Total age of 5 students = (5×14)years = 70years
Total age of other 9 students = (9×16)years = 144years
∴ Age of the 15th student = 225−(70+144) = 225−214 = 11years.