The answer depends on how many days Todd is going to want to go swimming. To show this on a graph, we would first have to work out what y would be. We do this by substituting values into x, until we notice a pattern on the linear graph (we know the graph will be linear as there are no x² values.
If x is the number of days and y is the cost
a) y = 0x + 70 or y = $70
If there is no daily cost, then the price will always remain $70. (Blue)
There will be a horizontal line intersecting the y axis at $70.
b) y = 4x + 15
The initial cost in addition to whatever the number of days is, multiplied by $4 per day.
Day 1: (4 x 1) + 15 = $19
Day 2: (4 x 2) + 15 = $23
Day 3: (4 x 3) + 15 = $27
Day 4: (4 x 4) + 15 = $31
By now, we should be able to notice a pattern, the y value always increases by $4, after starting at y = $19
On the graph, after plotting these 4 points, we would just continue the straight line along until it spreads across the entire graph.
c) y = 6x
The total cost for all the sessions will be the number of days multiplied by the cost per day.
As it is 6 multiplied by the number of days, we must write out the 6 times table:
x = 1 2 3 4 5 6 7 8 9 10
y = 6, 12, 18, 24, 30,36, 42, 48, 54, 60 etc.
Just plot some of these co-ordinates on the line (at least three to be sure) and check that they make a straight line. They are correct if they do.
After plotting all these co-ordinates, we will get something that looks like the image attached.
This tells us that daily pay is cheaper, until 8 days have passed. After that, it gets increasingly pricier to pay per day. Deposit plus then becomes the cheapest until the 14 day mark, where it then becomes cheaper to have paid the Early pay. From then onwards, early pay would have been the best option to choose.
Daily Pay - up to and including 7 days
Deposit Plus - up to and including 13 days
Early Pay - 14 days or more.
Not sure how much you needed on this question
