A jar contains only red and blue marbles. The probability of randomly selecting a red marble is .
Compare Quantity A and Quantity B, using additional information centered above the two quantities if such information is given, and select one of the following four answer choices.
Column A: The ratio of the number of red marbles to the number of blue marbles
Column B:
- The quantity in Column A is greater.
- The quantity in Column B is greater.
- The two quantities are equal. (correct answer)
- The relationship cannot be determined from the information given.
Explanation: This question tests Quantitative Comparison reasoning with probability and ratios. The key strategy is to convert the given probability into a ratio. If the probability of selecting a red marble is 3/5, then out of every 5 marbles, 3 are red and 2 are blue (since the jar contains only red and blue marbles). Therefore, the ratio of red marbles to blue marbles is 3:2, which can be written as the fraction 3/2. Column B is also 3/2. Since both columns represent the same value, they are equal. A common error would be to confuse the probability (red marbles/total marbles = 3/5) with the ratio (red marbles/blue marbles = 3/2), but careful analysis shows that if 3/5 of all marbles are red, then 2/5 are blue, giving the ratio 3/2.