Question

I need help with this becuase i dont get it

Answer 1

Given the function that determines the bill:

`b(x)=\begin{cases}0.15x\text{ , }x\leq200^{} \\ \\ 0.10(x-200)+30,\text{ }x>200\end{cases}\text{ }`

You know that "x" represents the number of kilowatt-hours (kWh) used in a month

Since you have to find the bill for a person who uses 400 kWh in a month, you can need to use the second equation, because the value of "x" is, in this case:

`x=400`

And:

`400>200`

Therefore, substituting that value of "x" into the second equation and evaluating, you get:

`\begin{gathered} b(x)=0.10(x-200)+30 \\ \\ b(400)=0.10(400-200)+30 \end{gathered}`

`\begin{gathered} b(400)=0.10(200)+30 \\ \\ b(400)=20+30 \\ \\ b(400)=50 \end{gathered}`

Hence, the answer is: Option A.