A ratio compares quantities. If a pattern uses 2 blue tiles for every 3 yellow tiles, its blue-to-yellow ratio is 2:3. Doubling both quantities gives 4:6, the same ratio.
Worked example
A mix uses 3 cups of water for 2 cups of concentrate. For 8 cups of concentrate, multiply both quantities by 4: use 12 cups of water.
Practice
- Write 6:9 in simplest form.
- A map scale represents 4 km with 1 cm. What does 7 cm represent?
- Five identical notebooks cost $15 in a fictional shop. What would eight cost at the same unit price?
- A ratio is 3:5. If the first quantity is 18, what is the second?
Show answers and reasoning
- 2:3.
- 28 km.
- $24: $3 each × 8.
- 30: both parts were multiplied by 6.