Question 173563
The way to look at this is that you're graphing 
price on the y-axis and cups on the x-axis.
Each point on the graph is (x,y) = (cups,price)
The problem gives you
(50,1) and
(25,2)
Since the problem says the relation is linear,
write the general equation for a straight line
{{{y = mx + b}}} where
m = slope
b = y-intercept
Now plug in the given points one at a time
(1) {{{1 = m*50 + b}}} and
(2) {{{2 = m*25 + b}}}
Solve for {{{m}}} and {{{b}}}
Subtract (1) from (2)
{{{1 = -25m}}}
{{{m = -(1/25)}}}
Plug this back into (2)
{{{2 = -(1/25)*25 + b}}}
{{{2 = -1 + b}}}
{{{b = 3}}}
So, the equation is
{{{p = -(1/25)*c + 3}}} answer
check the answer
Does it pass through the given points?
(50,1)
{{{1 = -(1/25)*50 + 3}}}
{{{1 = -2 + 3}}}
{{{1 = 1}}}
(25,2)
{{{2 = -(1/25)*25 + 3}}}
{{{2 = -1 + 3}}}
{{{2 = 2}}}
OK
If the price is {{{0}}} the equation says I'll sell
{{{75}}} cups. I'd probably sell a lot more
When the price is $3, the equation says i'll sell
no cups because it's too expensive