Math Help , Oh snap.

[jspeicher]

Residents are connected to a water supply and are billed a fixed amount yearly plus a charge for each cubic foot of water used.

A household using 1000 cubic feet is billed $90
A household using 1600 cubic feet is billed $105

a) What is charge per cubic foot?
The yearly charge would cancel since they are the same, so don't I just find the slope to find the charge per cubic foot?

b) Write an equation for the total cost of a resident's water as a function of cubic feet of water used.
This would be a linear line correct?

Don't need direct answers, just some help in the right direction.

 

[Whitecloak]

dumbass

a) 2.5 cents
b) 65 + 0.025* usage

 

[MrChad]

a) Yes.
b) Yes.

 

[MrChad]

Originally posted by: whitecloak
dumbass

a) 2.5 cents
b) 65 + 0.025* usage

He didn't ask for direct answers. :roll:

 

[BrokenVisage]

Oh snap?

 

[Whitecloak]

Originally posted by: MrChad

Originally posted by: whitecloak
dumbass

a) 2.5 cents
b) 65 + 0.025* usage

He didn't ask for direct answers. :roll:

and why should I give a fu[/i]ck?

 

[jspeicher]

Well, thanks anyway, those are what I got as well. Thank you.

 

[birdpup]

These are two points on a graph.
X = cubic feet
Y = $

Draw the graph and see it visually.
Then find the appropriate formula to verify your visual results.

EDIT:
I was thinking more like
m = (Y2 - Y1) / (X2 - X1)

Y = mX + b

point-slope form
Y2 - Y1 = m * (X2 - X1)

but the two-equation style used by the others also works well.

 

[yobarman]

1000x + y = 90
1600x + y = 105

y = 90 - 1000x
y = 105 - 1600x

105 - 1600x = 90 - 1000x

15 = 600x

x = .025
y = 65

 

[iamwiz82]

1000x + y = 90

1600x+ y = 105

 

[DingDingDao]

Originally posted by: BrokenVisage
Oh snap?

Okay that made me laugh :laugh:

 

[BlueWeasel]

Originally posted by: whitecloak
dumbass

a) 2.5 cents
b) 65 + 0.025* usage

Wow, what a douchebag.

 

[Whitecloak]

Originally posted by: BlueWeasel

Originally posted by: whitecloak
dumbass

a) 2.5 cents
b) 65 + 0.025* usage

Wow, what a douchebag.

Yes, I am, aren't I?