Question:
If the wholesale price for a product is $100, and the item sells at retail for $150, what is the retail markup percentage?

Answer:
The amount of markup was $50.
What percent of $100 is $50?
$50 equals 50% of $100.
So the markup percentage = 50%

The mathematical equation to this problem is as follows:
WAY 1 - easier. Set up equation, isolate 100X, solve right hand side, isolate X by dividing both sides by 100, solve the problem, *convert the decimal to a percent.
Step 1: 100 + 100X = 150
Step 2: 100X = 150 - 100
Step 3: 100X = 50
Step 4: X = 50/100
Step 5: X = 1/2 = .5

WAY 2 ( a little more complicated)
First, set up the equation. Next, factor out the common factor of 100. Then work on isolating X.....
Step 1: 100 + 100X = 150
Step 2: 100(1 + X) = 150
Step 3: 1 + X = 150/100
Step 4: 1 + X = 15/10
Step 5: 1 + X = 1.5
Step 6: X = .5

*To go from decimals to percentage then move the decimal over two places to the right and add the percent sign. Ex: .5 = 50%; .33 = 33%; 3.37 = 337%