To solve this problem we will need a system of equations.
Step 1. Find the first equation.
Using the statement "Emma rented a bike for 4 hours and paid £18", we will call the cost per hour h, and the flat fee f. Thus, the first equation is:
This is because Emma rented the bike for 4 hours but she had to pay a flat fee f, and the total was £18.
Step 2. Find the second equation.
We do the same but now with the statement "Louise rented a bike for 7 hours and paid £25.5". Remember that for our equation, h represents the cost per hour and f the flat fee. The second equation is:
Step 3. In summary, our system of equations is:
Step 4. To solve part a. we have to find the cost per hour "h".
To find it, we use the elimination method in our system of equations, which consists of adding or subtracting the equations in order to eliminate one variable.
Since we are interested in finding "h", we can subtract the second equation from the first one, and we get the following:
Applying the subtraction:
And we start subtracting 7h-4h, which results in 3h:
The next subtraction is f-f, which results in 0.
And then, subtract 25.5-18:
The equation we have as a result is:
Which is an equation we can use to solve for the cost per hour h.
Dividing both sides by 3:
The cost per hour is £2.5
Step 5. To find part b we need to find the rental feed, in our case, this means to find "h".
Using the first equation of the system:
And substituting the previous result:
We get:
Solving the operations:
And solving for f:
the flat fee is £8.
Step 6. To find part c, we consider the cost per hour and the flat fee.
Michael rented the bike for 2 hours.
Since the cost per hour is £2.5, and the flat fee is £8, he will pay:
Solving these operations:
It will cost £13.
Answer:
a. £2.5
b. £8
c. £13