Question 39

The average of marks of 17 students in an examination was calculated as 71. But it was later found that the mark of one student had been wrongly entered as 65 instead of 56 and another as 24 instead of 50. The correct average is

Solution

Average marks of 17 students = 71

=> Total marks of 17 students = $$71 \times 17=1207$$

Now, 65 is replaced with 56 and 24 with 50

=> Correct total marks = $$1207+(56-65)+(50-24)$$

= $$1207-9+26=1224$$

$$\therefore$$ Correct average = $$\frac{1224}{17}=72$$

=> Ans - (C)

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