Percent of change markup discount

You calculate the markup or markdown in absolute terms (you find by how much the quantity changed), and then you calculate the percent change relative to the original value. So they're really just another form of "increase - decrease" exercises.

Example:

A computer software retailer used a markup rate of 40%. Find the selling price of a computer game that cost the retailer $25.
The markup is 40% of the $25 cost, so the markup is:

(0.40)(25) = 10
Then the selling price, being the cost plus markup, is:

25 + 10 = 35

The item sold for $35.

20y5 times 2 is 1010 times -2 is -20, plus y