Firstly, let's create a function of f(t) where t represents the time that has past, and f(t) represents the amount of rainwater. We know that when t=1, then f(t)=10, and t=2 then f(t)=15. So, let's take that and analyze it:
(1,10)
(2,15)
m = (15-10)/(2-1) = 5
y-intercept = 5
∴ f(t) = 5t+5
Now we just evaluate t for 10:
f(10) = (5*10)+5
f(10) = 55
Well lets see. You have a total of 52 marbles. So all you would have to do would be to find the percent of 52 out of 60. This sounds confusing and I may not be completely right but I hope you give it a shot!
Answer:
Part A) For the number of hours less than 5 hours it make more sense to rent a scooter from Rosie's
Part B) For the number of hours greater than 5 hours it make more sense to rent a scooter from Sam's
Part C) Yes, for the number of hours equal to 5 the cost of Sam'scooters is equal to the cost of Rosie's scooters
Part D) The cost is $90
Step-by-step explanation:
Let
x-------> the number of hours (independent variable)
y-----> the total cost of rent scooters (dependent variable)
we know that
Sam's scooters
Rosie's scooters
using a graphing tool
see the attached figure
A. when does it make more sense to rent a scooter from Rosie's? How do you know?
For the number of hours less than 5 hours it make more sense to rent a scooter from Rosie's (see the attached figure) because the cost in less than Sam' scooters
B. when does it make more sense to rent a scooter from Sam's? How do you know?
For the number of hours greater than 5 hours it make more sense to rent a scooter from Sam's (see the attached figure) because the cost in less than Rosie' scooters
C. Is there ever a time where it wouldn't matter which store to choose?
Yes, for the number of hours equal to 5 the cost of Sam'scooters is equal to the cost of Rosie's scooters. The cost is $70 (see the graph)
D. If you were renting a scooter from Rosie's, how much would you pay if you were planning on renting for 7 hours?
Rosie's scooters

For x=7 hours
substitute

The cost is $90