Multiple choice

The average age of $35$ students in a class is $16$ years. The average age of $21$ students is $14$. What is the average age of remaining $14$ students?

  1. $15$ years
  2. $17$ years
  3. $18$ years
  4. $19$ years
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

The total age of 35 students is 35 * 16 = 560. The total age of 21 students is 21 * 14 = 294. The remaining 14 students have a total age of 560 - 294 = 266, so their average age is 266 / 14 = 19.

AI explanation

Using the formula for overall average, the total age of all 35 students is 35 times 16, which equals 560 years. The total age of the first 21 students is 21 times 14, giving 294 years. The total age of the remaining 14 students is 560 minus 294, yielding 266 years. Dividing this sum by 14 gives an average age of 19 years.