The city's water company charges a fee of $20 a month in addition to $0.25 per every gallon used. Using the function c=0.25x+20, where c is the total cost per month for water services and x is gallons used, which of the following points on the graph accurately represents a monthly usage of 1,200 gallons?

Question

(1200, 300)
(1200, -180)
(320, 1200)
(1200, 320)

Answer 1

To find the total cost \( c \) for a monthly usage of 1,200 gallons of water, we can substitute \( x = 1200 \) into the cost function \( c = 0.25x + 20 \):

\[ c = 0.25(1200) + 20 \]

Calculating this:

\[ c = 300 + 20 = 320 \]

Thus, when using 1,200 gallons, the total cost is $320. The point that accurately represents this monthly usage would be \( (1200, 320) \).

So, the correct answer is:

(1200, 320).