Answer: The ratio of red marbles to blue marbles is 3:6. This can be written as a fraction as 3/6, which simplifies to 1/2.
Explanation:
To find the ratio of two quantities, you can divide the number of one type of item by the number of another type of item. In this case, the ratio of red marbles to blue marbles is 3 marbles / 6 marbles, which simplifies to 1/2.
It's important to note that a ratio is not the same thing as a percentage or a fraction. A ratio is a comparison of two quantities, while a percentage is a measure of a quantity relative to the total amount and a fraction is a division of one number by another.