Question

Residents of the town of Maple Grove who are connected to the municipal water supply are billed a fixed amount monthly plus a charge for each cubic foot of water used. A household using 1900 cubic feet was billed $156, while one using 2600 cubic feet was billed $184. (a) What is the charge per cubic foot? dollars per cubic foot (b) Write an equation for the total cost, c, of a resident's water, , as a function of cubic feet of water used. c(w) = dollars c) How many cubic feet of water used would lead to a bill of $216? cubic feet

Answer 1

9514 1404 393

Answer:

• $0.04 per cubic foot
• c(w) = 0.04w +80
• 3400 cubic feet

Explanation:

(a, b) We are given two pairs of values:

(w, c) = (1900, 156) and (2600, 184)

so we can write the equation of the relationship using the 2-point form of the equation of a line.

y = (y2 -y1)/(x2 -x1)(x -x1) +y1

c = (184 -156)/(2600 -1900)(w -1900) +156 . . . . . substitute given points

c = 28/700(w -1900) +156

c(w) = 0.04w +80

The charge per cubic foot is $0.04.

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(c) For a bill of $216, the amount of water used is ...

216 = 0.04w +80

136 = 0.04w

3400 = w

Use of 3400 cubic feet of water would lead to a bill of $216.