Question

The average of marks of 14 students was calculated as 71. But it was later found that the mark of one student had been wrongly entered as 42 instead of 56 and of another as 74 instead of 32 . The correct average is? solve the question by using allegation and mixture formula.​

Answer 1

Answer:

69

Step-by-step explanation:

total no. of marks gain by students

$= 14 \times 71$

$= 994$

total no. of correcting marks =

$(994 - 42 + 74) \: + 56 + 32$

$= 966$

new average marks of students =

$\frac{total \: no \: of \: marks \: of \: student}{no. \: of \: student}$

$= \frac{966}{14}$

$= 69$