|the shop at bluebird, 350 King's Road, London|
|Anthropologie, Regent Street store, London|
If the cost is known and the percentage markup is known, the sale price is the original cost plus the amount of markup. For example, if the original cost is £4.00 and the markup is 25%, the sales price should be £4.00 + £4.00*25/100 = £5.00.
A faster way to calculate the sale price is to make the original cost equal to 100%. The markup is 25% so the sales price is 125% of the original cost. In the example, £4.00 * 125/100 = £5.00.