Question

Winston has just received his monthly credit card statement. He placed eight charges on his card in the last month with a mean of $39.77 Per charge. He knows that seven of the charges were as follows determine the amount of the eighth charge

Answer 1

Given:

Number of charges = 8

Mean charge = $39.77

Other seven charges: $46.06, $39.70, $47.29, $39.13, $44.66, $38.53, $46.89

Let's find the eight charge.

Apply the formula for mean:

`mean=\frac{sum\text{ of charges}}{number\text{ of charges}}`

Let x represent the eight charge.

We have:

Sum of charges = $46.06 + $39.70 + $47.29 + $39.13 + $44.66 + $38.53+ $46.89 + x = $302.26 + x

Thus, we have:

`\begin{gathered} 39.77=(302.26+x)/(8) \\ \\ \text{ Multiply both sides by 8:} \\ 39.77*8=(302.26+x)/(8)*8 \\ \\ 318.16=302.26+x \\ \end{gathered}`

Solving further:

Subtract 302.26 from both sides

`\begin{gathered} 318.16-302.26=302.26-302.26+x \\ \\ 15.9=x \\ \\ x=15.9 \end{gathered}`

Therefore, the eight charge is $15.90

ANSWER:

$15.90