A yearbook printer charges based on the number of pages printed. Here is a table that shows the cost of some recent yearbooks.
|Number of pages||50||100||150||200|
Which equation gives the cost, y, in terms of the number of pages, x?
The costs (y) are going up by 0.80 andthe pages (x) is going up by 50
so the gradient is rise /run = change in y/change in x = 0.8/50 = 0.016
y= 0.016x + something
Substitute any of the known values into the equation to find what that something (b) (yintercept) is.
Check by subing in a different pair and checking that it works.
You can post your working if you are not sure that your understand.
the only thing I understood about that answer is that D is definitely not the answer
One known value is
y= 2.55 when x=100
I have told you that y= 0.016x + something
Sub in your known values of x and y to find out the value of b
(which is the y intercept or the cost of prinint irrespective of the number of pages.)
2.55 = 0.016*100 +b
Now you can solve this to get the missing b value.