The average marks in mathematics scored by the students of a school at the public examination were 39. If four of these students who actually scored 5, 12, 15 and 19 marks at the examination had not been sent up, the average marks for the school would have been 44. Find the number of students sent up for examination from the school?
- 20
- 25
- 30
- 32
Explanation
Given:
- Average marks of all students = 39
- Scores of 4 students = 5, 12, 15, 19
- New average after removing these 4 students = 44
- Number of students = ? (Let it be N)
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Step 1: Calculate total marks of all students
Total marks = Average × Number of students = 39 × N
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Step 2: Calculate total marks of 4 students
Sum of marks of 4 students = 5 + 12 + 15 + 19 = 51
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Step 3: Calculate total marks of remaining students
Total marks after removing 4 students = 44 × (N - 4)
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Step 4: Equation
Total marks of all students - marks of 4 students = total marks of remaining students
=> 39N - 51 = 44 (N - 4)
=> 39N - 51 = 44N - 176
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Step 5: Solve for N
44N - 39N = 176 - 51
5N = 125
N = 125 / 5 = 25
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اس سوال کو وضاحت کے ساتھ پڑھیں
- 0
- 1
- 2
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- 30
- 35
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- 45
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