Problema Solution
The cost c of water is a linear function of n, the number of gallons used. If 1,000 gallons cost $4.70 and 9,000 gallons cost $14.30, express c as a function of n.
Answer provided by our tutors
C = a*n + b
4.7 = a*1000 + b
14.3 = a*9000 + b
Subtracting the first equation from second, we get
9.6 = a*8000
a = 0.0012, using this in Eq. 1 we get
b = 3.5
C = 0.0012*n + 3.5