Question

There are 7 red marbles and 9 blue marbles in a bag. What is the ratio of all marbles in the bag to blue marbles? What is the ratio of red marbles to blue marbles?

Answer 1

Answer to the 1st question is: 16/9 or 16:9 (whichever form you use)

Answer to the 2nd question is: 7/9 or 7:9

Explanation:

Key skills needed: Number theory, Ratios, and Fractions

1) Let's look at the first question. A ratio is usually a number of something over a number of another thing. One such example is 5 apples : 4 oranges (or 5 apples/ 4 oranges - whichever form you write in).

1. Based on that let's look at the first problem. We want to find the ratio of all the marbles in the bag to the blue marbles. So it would be --> the total # of marbles over the number of blue marbles.
2. The total number of marbles is 7+9= 16. This would be our first number, or the numerator.
3. The number of blue marbles is 9. This would be our 2nd number, or the denominator of the ratio.
4. With this information --> The ratio would be 16/9 or 16:9

2) Now let's look at the 2nd question. The number of red marbles to the number of blue marbles is the ratio we need to find.

1. The number of red marbles is 7. This would be our first number or the numerator.
2. The number of blue marbles is 9. This would be our second number or the denominator.
3. Therefore, the ratio would be --> 7/9 or 7:9

Hope you understood and have a nice day!! :D