NECO 2022 · Paper 1 · Q52

The mean of the following set of data: 5, 7, 9, $x$ and 6 is 6. Determine the value of $x$ .

Worked solution (try it first)

There are 5 numbers with mean 6, so they add up to $5 \times 6 = 30$ .
The known numbers add up to $5 + 7 + 9 + 6 = 27$ , so $x = 30 - 27 = 3$ , option B.