Question

If the monthy cost for 23 HCF is $48.31 , what is the monthly cost for 18 HCF?

Answer 1

Find the equation of the graph:

General Equation : y = mx + b

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Given that the gradient is 1.45

Sub m = 1.45:

y = 1.45x + b

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Find b:

Given that x = 23, y = 48.31:

48.31 = 1.45(23) + b

b = 14.96

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Equation of the graph:

y = 1.45x + 14.96

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When x = 18:

y = 1.45(18) + 14.96 = $41.06

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Answer: $41.06