Numerical answer
The average marks of 25 students in a class is 62. Two students who scored 45 and 51 leave the class and three new students join. The average of the 26 students now in the class is 64. What is the average mark of the three new students?
Show answer and solution
Answer: 70
Original total = 25 × 62 = 1550.
After the two students leave: 1550 − 45 − 51 = 1454 (23 students).
New total for 26 students = 26 × 64 = 1664.
So the three new students together scored 1664 − 1454 = 210, and their average = 210 ÷ 3 = 70.
Tip: In average problems always work with totals – add and subtract marks, never averages.
After the two students leave: 1550 − 45 − 51 = 1454 (23 students).
New total for 26 students = 26 × 64 = 1664.
So the three new students together scored 1664 − 1454 = 210, and their average = 210 ÷ 3 = 70.
Tip: In average problems always work with totals – add and subtract marks, never averages.
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