Answer:
The number of red marbles in the bag are 114.
Explanation:
Given:
Total marbles in the bag is 120. There are 19 marbles for every black marble.
Now, to get how many red marbles in the bag.
Let the black marbles be
.
And the red marbles be
.
According to question:
![x+19x=120](https://img.qammunity.org/2020/formulas/mathematics/middle-school/yfh3b8a0pu7p933mcsgv3jv50p1aol2rqr.png)
![20x=120](https://img.qammunity.org/2020/formulas/mathematics/middle-school/woyd3naj4y0gguchvztxgdecfffkzlw6o5.png)
Dividing both sides by 20 we get:
![(20x)/(20)=(120)/(20)](https://img.qammunity.org/2020/formulas/mathematics/middle-school/uoqc34ehy1s9njjccsvty6busyvu8l29xa.png)
![x=6](https://img.qammunity.org/2020/formulas/mathematics/middle-school/iytjkob8c453cdntkigo6vyjyk3yzlat9o.png)
Black marbles = 6
So, the red marbles = 19×6 = 114.
Therefore, the number of red marbles in the bag are 114.