A class has 12 boys and 8 girls. What is the ratio of boys to all students in the class?
A3:2
B2:3
C3:5
D2:5
There are 12 + 8 = 20 students total. The ratio of boys to all students is 12:20. Simplifying by dividing both by 4 gives 3:5. This is a part-to-whole ratio, not a part-to-part ratio (which would be 12:8 = 3:2).
Question 2 True / False
The ratio 4:6 is equivalent to the ratio 6:4.
TTrue
FFalse
Answer: False
Order matters in a ratio. 4:6 means 4 for every 6 (for example, 4 cups of one ingredient per 6 of another), while 6:4 is the reverse proportion. Reversing the terms gives a different comparison. Both can be simplified (4:6 = 2:3, and 6:4 = 3:2), but they represent different relationships.
Question 3 Short Answer
A lemonade recipe uses a ratio of 2 cups of lemon juice to 5 cups of water. If you want to make enough to use 8 cups of lemon juice, how many cups of water do you need?
Think about your answer, then reveal below.
Model answer: 20 cups
The ratio 2:5 means for every 2 cups of lemon juice you use 5 cups of water. Scaling up by a factor of 4 (since 8 ÷ 2 = 4) gives 5 × 4 = 20 cups of water. Ratios scale proportionally — multiply both parts by the same factor.