Question : The average score of 40 students in an examination was 25. It was later found that the marks of one student had been wrongly entered as 73 instead of 37. What is the value of the correct average?
Option 1: 24.3
Option 2: 24.1
Option 3: 24.5
Option 4: 24.7
Correct Answer: 24.1
Solution :
Given: The average score of 40 students was 25.
A wrong entry of 73 marks instead of 37 marks is also included.
Total score of the students ⇒ 40 × 25 = 1000
Difference made by the wrong entry of 73 marks instead of 37 marks = 73 – 37 = 36
So, the total marks of the students = 1000 – 36 = 964
Average value = $\frac{\text{Sum of the observations}}{\text{Total number of observations}}$
So, Average marks of 40 students = $\frac{\text{964}}{\text{40}}=24.1$
Hence, the correct answer is 24.1.
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