What is the ratio of blue balls to total balls?

• A. 1:2
• B. 1:3
• C. 1:1
• D. 2:3

Answer: (A)

Ratio compares a part to the whole. Here, blue balls to total balls is blue:total. To find it, count how many blue balls there are and how many balls there are in total, then reduce to the smallest whole-number terms. If the ratio is 1:2, that means for every two balls, one is blue—blues make up exactly half of the collection. Examples that fit this are 1 blue out of 2 total, 2 blue out of 4 total, or 3 blue out of 6 total, all simplifying to 1:2. So this describes half the balls being blue, which is why 1:2 is the correct description. Other ratios would indicate different fractions (one-third, two-thirds, or all blue) and wouldn’t match the counts in this scenario.