The city’s water company charges a fee of $20 a month in addition to a $0.25 per every gallon used. Using the function c=0.25x+20

𝑐
=
0.25
𝑥
+
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?(1 point)
Responses

(320,1,200)
(
320
,
1
,
200
)
left parenthesis 320 comma 1,200 right parenthesis

(1,200,320)
(
1
,
200
,
320
)
left parenthesis 1,200 comma 320 right parenthesis

(1,200,−180)
(
1
,
200
,

180
)
left parenthesis 1,200 comma negative 180 right parenthesis

(1,200,300)

1 answer

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

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

Calculating \( 0.25 \times 1200 \):

\[ 0.25 \times 1200 = 300 \]

Now add the fixed fee:

\[ c = 300 + 20 = 320 \]

Thus, the total cost for using 1,200 gallons of water is $320. The point that accurately represents this monthly usage is \( (1,200, 320) \).

From the options you provided:

  • \( (320, 1,200) \)
  • \( (1,200, 320) \)
  • \( (1,200, -180) \)
  • \( (1,200, 300) \)

The correct answer is (1,200, 320).