Question

The mean number of emails adele received during a week was 51.

The numbers received for the six days were 39, 57, 70, 45, 71, 32.Find how many emails she received on the seventh day. ​

Answer 1

Given:

The mean number of emails adele received during a week was 51.

The numbers received for the six days were 39, 57, 70, 45, 71, 32.

To find:

The number of emails received on the seventh day.

Solution:

Let x be the number of emails received on the seventh day.

We know that,

`\text{Mean}=\frac{\text{Sum of observations}}{\text{Number of observations}}`

`51=(314+x)/(7)`

Multiply both sides by 7.

`357=314+x`

Subtract 314 from both sides.

`357-314=x`

`43=x`

Therefore, she received 43 emails on the seventh day.