Question

A water district has been charging its customers a flat rate of $3.25 per HCF. Because of a drought emergency, it is instituting a block rate of $3.40 for the first 20 HCF and $4.35 for the next 40 HCF. If a family uses an average of52 HCF per month, by what percent would their average bill increase under the block systemTheir average bill under the block system would increase by __%

Answer 1

Given:

A water district has been charging its customers a flat rate of $3.25 per HCF. Because of a drought emergency, it is instituting a block rate of $3.40 for the first 20 HCF and $4.35 for the next 40 HCF.

Required:

Need to find out the percentage of average bill increase under the block system for a family which uses 52 HCF per month.

Explanation:

The average bill for the family under the normal rate is;

$\begin{gathered} =3.25\times52 \\ =169\text{ dollars} \end{gathered}$

The average bill for the family under the block rate is;

$\begin{gathered} =(20\times3.40)+(32\times4.35) \\ =68+139.20 \\ =207.2\text{ dollars} \end{gathered}$

Average bill increase is;

$\begin{gathered} =207.2-169 \\ =38.2\text{ dollars} \end{gathered}$

Percentage of average bill increase under the block system is;

$\begin{gathered} =\frac{38.2}{169}\times100 \\ =22.60\% \end{gathered}$

Final Answer:

$22.60\%$