Answer:
114 marbles.
Step-by-step explanation:
Let the number of red marbles be r
Let the number of black marbles be b
Given the following data;
Total number of marbles = 120
Translating the word problem into an algebraic equation, we have;
[tex] r = 19b[/tex] .......equation 1
[tex] r + b = 120[/tex] ........equation 2
Substituting the value of "r" into equation 2, we have;
[tex] 19b + b = 120[/tex]
[tex] 20b = 120[/tex]
[tex] b = \frac {120}{20}[/tex]
b = 6 marbles.
To find the number of red marbles;
From equation 1;
[tex] r = 19b[/tex]
Substituting the value of "b" into equation 1, we have;
[tex] r = 19*6[/tex]
r = 114 marbles.
Therefore, there are 114 red marbles in the bag.