Question

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

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,

$\text{Mean}=\dfrac{\text{Sum of observations}}{\text{Number of observations}}$

$51=\dfrac{314+x}{7}$

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.