The answer is going to be yes it's rational. hope that helped
Answer:

Step-by-step explanation:
Let
x------> the number of days
y----> the cost of renting a car
we know that
For 

For 
The rate is equal to

so

In this problem. the car has been rented for more than a week
therefore

The cost of renting a car is equal to

The answer is 90%. You get this answer by multiplying both the numerator and denominator by 5 so 18x5=90 and 20x5=100 giving you a fraction of 90/100 and a percentage of 90%.