% Change = [(New - Original) ÷ Original] × 100
From $100 to $120:
(120-100)/100 × 100 = 20% increase
Percentage = (X ÷ Y) × 100
25 is what % of 200?
(25 ÷ 200) × 100 = 12.5%
Whole = X ÷ (Y ÷ 100)
15 is 20% of what?
15 ÷ 0.20 = 75
Amount = (X ÷ 100) × Y
15% of 200:
(15 ÷ 100) × 200 = 30