Question

what is the amount due for phone lines?
monthly utilities
electricity: $0.10/kwh, usage 3,500 kwh, amount due $350.00
water: $0.05/10 gal, usage 6,500 gallons, amount due $32.50
gas: $1/100 cubed ft, usage 4,900 cubed feet, amount due $49.00
phone lines: $45/line, usage 2 lines, amount due $?
international minutes: $0.09/minute, usage 30 minutes, amount due $2.70
internet service: $120/month, flat charge per month, amount due $120.00

Explanation:

Step1: Analyze the formula for amount due

The formula for the amount due is $\text{Amount Due}=\text{\$ Billed per Unit}\times\text{Usage}$.

Step2: Substitute the values for Phone Lines

For Phone Lines, the $\text{\$ Billed per Unit}=\$45$/line and the $\text{Usage} = 2$ lines. So, $\text{Amount Due}=45\times2$.

Step3: Calculate the result

$45\times2 = 90$.

Answer:

$\$90.00$