The given data can be tabulated as:
Number of swimsuits, s (x) Price, p (y)
0 0
2 23
4 46
6 69
8 92
10 115
We can see that by looking alone, the value of price p is increasing at a constant rate of 23 therefore the equation relating s and p must be linear in the form of:
y = m x + b
or
p = m s + b
where m is the slope of the line and b is the y intercept
The slope m can be calculated using the formula below and any two data points:
m = (y2 – y1) / (x2 – x1)
m = (23 – 0) / (2 – 0)
m = 11.5
The value of b (y-intercept) is the value of y when x = 0, therefore b = 0
The whole equation then becomes:
p = 11.5 s
