Real-world applications
Choose reference amounts and ratios in discount, growth, concentration, and scale problems.
Meaning
In ratio applications, identify the given reference amount, ratio, and comparison amount. Interpret discounts and increases as changes relative to a reference.
Example
A 15% discount on 40,000 won is 6,000 won, leaving a payment of 34,000 won. A 15% discount is fifteen hundredths of the original price, so the reduction is 40,000×0.15=6,000 won. Alternatively, multiply by the remaining fraction 1−0.15=0.85 to obtain 34,000 won directly. The 15% discount and the remaining 85% differ. This is a discount example; concentration and scale require their own unit checks.
Practice for this concept
Scope and references
Topics
Discounts, percentage increases and decreases, concentration, scale, finding original amounts
Learning goal
Choose reference amounts and ratios in discount, growth, concentration, and scale problems.
Helpful background
Decide what counts as the whole and connect percentages with unit rates.
Percentage applications
Does not include concentration or scale problems.