Number 1 and number 3 are the same because if you are purchasing three tires that is 75% off the tires you need and one of them you get free. the free one becomes the overall discount of 25% off. number 3 is the same, the one quarter represents 25% off of the purchase.
This is a proportion problem that involves cross-multiplication
Set your problem up like so:

=

Now cross multiply
2,000 x 3 = 6,000
now you're left with 5x = 6,000
Now divide by 5 on both sides
Answer is 1,200
Value of x is x=32
Step-by-step explanation:
We need to find the value of x of the equation 
Solving the equation and finding value of x

Adding 4 on both sides

Divide both sides by 0.5

So, value of x is x=32
Keywords: Solving Equations
Learn more about Solving Equations at:
#learnwithBrainly