Question

A bag contains 120 marbles. Some are red and the rest are black. There are 19 red marbles for every black marble. How many red marbles are in the bag? (Consider using a double number line, tape diagram, or ratio table)

Answer 1

there are 101 black marbles

Explanation:

Answer 2

Using a double number line, we found that there are 114 red marbles in the bag out of a total of 120 marbles, given that there are 19 red marbles for every black marble.

Let's represent the ratio of red to black marbles using a double number line. Given that there are 19 red marbles for every black marble, we can set up the diagram:

In this representation, each segment for red marbles corresponds to 19 marbles, and each segment for black marbles corresponds to 1 marble. The total number of segments for red marbles is 19 times the number of segments for black marbles.

Since there are 120 marbles in total, we can divide the segments equally:

19x + x = 120

Combining like terms:

20x = 120

Dividing by 20:

x = 6

Now, we can find the number of red marbles:

Red marbles = 19 times the number of segments for black marbles

Red marbles = 19 times 6 = 114

Therefore, there are 114 red marbles in the bag.