Respuesta :

Given:
X: The blue marbles.
3X: The red marbles.
A box contains 144 marbles.
SOLVING:
X + 3X = 144
4X = 144
X = [tex] \frac{144}{4}[/tex]
X = 36 ===> The blue marbles.

If there are 3 times as many red marbles as there are blue marbles:
3(36) = 108 ===> The red marbles. SOLUTION

TESTING:
[tex]36+108=144[/tex]
[tex] \boxed{144}=\boxed{144}\quad\checkmark\ The\ value\ is\ correct.[/tex]
GOOD LUCK...!!!