Answer:
14
Explanation:
Let's say Devaughn is x amount of years old and Sydney is y amount of years old.
Since the sum of their age is equal to 56, you would make the equation:
x+y=56
Now, set that aside and move on to the next step.
They are saying the Devaughn (x) is 3 times the number of years Sydney (y) is. So in mathematical terms you can create an equation stating:
3y=x because 3 times Sydney's age (y) would be Devaughn's age (x).
With the equations:
3y=x
x+y=56
You can plug in x in (x+y=56) as 3y because the other equation is saying that x is equal to 3y. So, that will give you 3y+y=56. Now, combine like terms or just simplify.
Simplifying 3y+y=56 would give you 4y=56, now just divide 56 by the 4 and you will get 14. This is saying that y=14. Now plug in y for the other equation (x+y=56):
x+14=56
Subtract 56 by 14 and it'll give you 42. That is saying x=42.
The question is asking for Sydney's age and i substituted her for the letter y which equaled 14.
Hope this helped :)