Maggie, an accountant, observes that her company purchased sets of juggling balls at a cost of $6 and is currently selling them at a price of $8.22. What is the mark-up, as a percentage?

Write your answer using a percent sign (%).

To calculate the mark-up percentage, we need to find the difference between the selling price and the cost price and then divide it by the cost price.

The mark-up is $8.22 - $6 = $2.22.

Dividing the mark-up by the cost price, we have $2.22 / $6 = 0.37.

To express this as a percentage, we multiply by 100: 0.37 *100 = 37%.

Therefore, the mark-up is 37%.