Description
Lynn found that in May her driving cost was $310 for 500 mi and in June her cost was $410 for 700 mi. Assume that there is a linear relationship between the monthly cost C of driving a car and the distance driven d.
Explanation & Answer
Assuming the relation between C and d is C=md+b
According to the description, d=500, C=310, so 500m+b=310 (1)
d=700, C=410, so 700m+b=410 (2)
Equation 2- Equation 1: 200m=100, m=0.5
Input m=0.5 to Equation 1, 500*0.5+b=310, 250+b=310, b=60
Therefore the relationship is C=0.5d+60