Question

Bryan’s monthly electric bill is determined by adding a flat administration fee to the product of the number of kilowatt hours of electricity used and the cost per kilowatt hour. When he uses 1,100 kilowatt hours of electricity, his bill is $113. When he uses 1,500 kilowatt hours of electricity, his bill is $153. What is the monthly administration fee?

Answer 1

@Haseeb96

Answer 2

as u know @justsmile531
Bryan's monthly electric bill is determined by adding a flat administration fee to the product of the number of kilowatt hours of electricity used and the cost per kilowatt hour.
okay let me take administration fee as ''x''

here
bryan's monthly electric bill = x + ( number of kilowatt hours of electricity multiply with cost per kilowatt hour )
okay

Answer 3

Ok , Now what

Answer 4

let the monthly administration fee be \(x\)
and let the cost per kilowatt hour be \(y\)

there fore
\(\large\tt \begin{align} \color{black}{1100\times y=113-x

}\end{align}\)

and
\(\large\tt \begin{align} \color{black}{1500\times y=153-x

}\end{align}\)

\(\large\tt \begin{align} \color{black}{\dfrac{1100\times y}{1500\times y}=\dfrac{113-x}{153-x}\\~\\
\dfrac{11}{15}=\dfrac{113-x}{153-x}\\~\\
\dfrac{15}{11}=\dfrac{153-x}{113-x}\\~\\
\dfrac{15-11}{11}=\dfrac{153-x-(113-x)}{113-x}\\~\\
\dfrac{4}{11}=\dfrac{40}{113-x}\\~\\
\dfrac{1}{11}=\dfrac{10}{113-x}\\~\\
113-x=110\\~\\
\huge x=3
}\end{align}\)

Answer 5

Sorry i could not solve your question because it is out of my knowledge

Answer 6

Thank you guys so much :)