Question 203589
Since the bill is a linear function, when one variable increases, the other increases too, or, when one variable decreases, so does the other.

Additionally, the slope of the line, along with the y-intercept will remain constant. We will therefore get: 	


{{{b(c) = 1.75(c) + y[i]}}}, where the bill (b) will be determined by c (the household’s consumption), and where {{{y[i]}}} is the y-intercept. In order to determine the value of {{{y[i]}}} though, we will need to substitute the other values.


{{{29.84 = 1.75(18) + y[i]}}}


{{{29.84 = 31.5 + y[i]}}}


{{{29.84 - 31.5 = y[i]}}}


{{{-1.66 = y[i]}}}


Therefore, our linear equation is: b(c) = 1.75(c) – 1.66


b(c)  =  1.75(14) – 1.66


b(c)  =  24.50 – 1.66


b(c)  =  22.84


The water bill, when consumption is 14 HCF is ${{{highlight_green(22.84)}}}