When I park my car in Mathstown, there are two car parks to choose from.
In car park A, it costs 80p to park for the first hour, and an extra 50p for each hour after that.
In car park B, it costs £1.50 to park for the first hour, and an extra 30p for each hour after that.
Which car park should I use?
This question depends on how long the person will stay in the parking lot. Let us use algebra.
Car park A: 80p(the first hour)+ y(50p)(the amount of hours = y, 50p = cost per hour).
Car park B: 150p(the first hour)+ y(30p)(the amount of hours = y, the cost per hour = 30p)
A: 80p+y(50p)
B: 150p+y(30p)
As now we have our formulae for A and B, let us implement that the driver will be stopping for 5 hours. So, y=5.
A: 80p+5(50p) = 80p+250p = 330
B: 150p+5(30p) = 150p+150p = 300
Now, let us implement that the driver will be stopping for only 3 hours. So, y=3.
A: 80p+3(50p) = 80p+250p = 230
B: 150p+3(30p) = 150p+150p = 240
We clearly can tell that this time, parking lot B is more expensive than parking lot A.
Now we have settled a conclusion.
When offering the cheapest parking lot price to drivers...
If you are stopping for a short period of time (a.k.a. less than 3 hours), then parking lot A is cheaper.
However, if you are stopping for a long period of time (a.k.a. more than 3 hours), then parking lot B is cheaper.