Answer:
a) 13 is a fix cost of the insurance, that doesn't depend on the number of days, 1.5 is the cost for each day of insurance.
b) Cost C = 28
c) d = 14 days
Explanation:
a) The term 13 is the inicial value of the insurance, that is, it is a fix cost that does not depend on the number of days of the insurance. The term 1.5*d means that for every day of the insurance, the cost will increase by 1.5, that is, each day of insurance costs 1.5.
b) To find this cost, we just need to use d=10 in the equation:
C = 13 + 1.5*10 = 13 + 15 = 28
c) if the insurance costs 34, we use C = 34 in the equation to find the value of d (number of days):
34 = 13 + 1.5*d
1.5*d = 21
d = 21/1.5 = 14 days
The length of the trip is 14 days