Linear cost equation

Question

At a candy ship, bubble gum costs 15 cents each and lolly pops costs 25 cents each (no tax). Emily has $3 to spend on bubble gum and lolly pops. Find the linear cost equation for the mix of candy Emily could buy and graph

Answer 1

Hi Savannah!

Gum + Lollipops = total

.15G +.25L = 3.00 

 

make a T-chart

Plug in values for L first because

Lollipops cost more than gum.

Just makes it easier. :)

G   ----- L

15         3

10         6

 

So, 15 gum + 3 Lollipops = $3

     (0.15)(15) + (0.25)(3) = 3

 

And, the same for 10 gum and 6 Lollipops

 

Now, you have two points

(15,3) and (10,6)

 

Find the slope = y₂-y₁/x₂-x_{1 = (-3/5)}

Use Point-Slope formula to get the 

equation of the line

y-y₁=m(x-x₁)

y - 3 = -3/5(x-15)

y = -3/5x + 12

 

When you graph it, the x-axis will be the gum

and the y-axis will be the lollipops.