Multiple choice

The average of ten students marks are 47. If $11^{th}$ student's marks are also included, then the average of eleven students marks becomes 45. Find the marks of $11^{th}$ student.

  1. $35$
  2. $25$
  3. $45$
  4. $40$
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Sum of 10 students = 10 * 47 = 470. Sum of 11 students = 11 * 45 = 495. 11th student = 495 - 470 = 25.

AI explanation

The total marks of the first ten students is 10 times 47, which equals 470. The total marks of all eleven students is 11 times 45, which equals 495. The marks of the eleventh student are the difference between the new total and the old total, so 495 minus 470 gives 25.

Keep practicing — related questions