The mean of the marks of 12 students is 54. When one more student joins the group, the mean of the marks of all 13 students becomes 55. What are the marks of the student who joined?
Answer & explanation
Correct answer: option 1
The correct answer is Option (1) → 67
The sum = mean × number of values. The marks of the new student are the difference between the total after joining and the total before.
Total marks of the 12 students \(=12\times54=648\)
Total marks of the 13 students \(=13\times55=715\)
Marks of the new student \(=715-648=67\)