To determine which example shows a markup on cost higher than 100%, we need to calculate the markup percentage for each option.

The formula for markup percentage is:

$\text{Markup Percentage} = \frac{\text{Selling Price} - \text{Cost}}{\text{Cost}} \times 100$

Now, let's apply this formula to each option:

1. Cost = $100; Expenses = $20; Profit = $80

   • Selling Price = Cost + Profit = $100 + $80 = $180
   • Markup = $\frac{180 - 100}{100} \times 100 = 80$ (This is not higher than 100%.)

2. Cost = $120; Markup = $100

   • Selling Price = Cost + Markup = $120 + $100 = $220
   • Markup Percentage = $\frac{220 - 120}{120} \times 100 = \frac{100}{120} \times 100 \approx 83.33$ (This is not higher than 100%.)

3. Cost = $100; Selling Price = $120

   • Markup Percentage = $\frac{120 - 100}{100} \times 100 = 20$ (This is not higher than 100%.)

4. Cost = $100; Selling Price = $220

   • Markup Percentage = $\frac{220 - 100}{100} \times 100 = 120$ (This is higher than 100%.)

Answer: The correct example is the fourth option:

• Cost = $100; Selling Price = $220, which gives a markup of 120%.

Would you like any further details on this? Here are some related questions you might find interesting:

1. What is the difference between markup and margin?
2. How can you calculate profit if you know the markup percentage and cost?
3. What happens if the markup percentage is too high?
4. How does understanding markup help in setting prices for products?
5. Can you give an example where the markup percentage is less than 50%?

Tip: Always remember that markup is based on the cost price, while margin is based on the selling price.