Question

The table shows information about water used in a household.

The value for April is missing.



The mean monthly water used for the six months is 18 m

Work out the value for April.

Answer 1

is there is no value of April

Explanation:

so the value of the month April is zero

Answer 2

The estimated water usage for April is
`19 \ m^3` to maintain an average monthly usage of
`18 \ m^3` over the six months.

To find the value for April, you need to use the mean (average) monthly water usage for the six months, which is given as
`18 \ m^3`.

The sum of the water usage for the six months is:

`\[16.2 + 18.1 + 15.9 + \text{April} + 17.8 + 21.0\]`

The mean is calculated by dividing the sum by the number of months (
`6` in this case):

`\[ \text{Mean} = \frac{{\text{Sum of water usage}}}{\text{Number of months}} \]`

Substitute the given mean (
`18`) and solve for the sum of water usage:

`\[18 = \frac{{16.2 + 18.1 + 15.9 + \text{April} + 17.8 + 21.0}}{6}\]`

Now, solve for the missing value (April). Multiply both sides of the equation by
`6` to isolate the sum:

`\[108 = 16.2 + 18.1 + 15.9 + \text{April} + 17.8 + 21.0\]`

Subtract the sum of the known values from
`108` to find the value for April:

`\[\text{April} = 108 - (16.2 + 18.1 + 15.9 + 17.8 + 21.0)\]`

`\[ \text{April} = 108 - (16.2 + 18.1 + 15.9 + 17.8 + 21.0) \]\[ \text{April} = 108 - 89 \]\[ \text{April} = 19 \]`