Question

The average grade in arithmetic for 30 Calcutta High School pupils is 89. If two students grades were misread as 58 and 67 instead of 81 and 72, the result would be the same. How do you calculate the right average?​

Answer 1

Answer:

the answer is in attachment

number are change I'm sorry

Answer 2

Solution :-

→ Average of 30 calcutta high school pupils = 89

So ,

→ Total sum of grades of all pupils = average * total = 89 * 30 = 2670 .

now,

→ Sum of grades of misread students = 58 + 67 = 125

and,

→ Correct sum of grades of these students = 81 + 72 = 153

then,

→ Actual sum of all students = 2670 - 125 + 153 = 2698

therefore ,

→ The correct average = 2698 / 30 = 89.93 (Ans.)

Hence, the right average of students will be 89.93 .

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