Question

The mean of a set of 7 no.is 91 if 1 no.is missing new mean is 88 find th.e misingno.

Answer 1

let the missing number be X

A/Q

$sum = 7 \times 91 = 637 \\ \\ and \\ \\ = > \frac{637 - x}{6} = 88 \\ \\ = > 637 - x = 528 \\ \\ = > x = 109$