Answer:
The sum of the larger and smaller number is 15.
Step-by-step explanation:
Let x = smaller number
Let y = larger number
Set up a system of equations.
2y - x = 21
2y + x = 27
Add the two equations together to cancel out x
4y = 48
Divide both sides by 4
y = 12
Plug value into either equation to find x
2(12) - x = 21
24 - x = 21
x = 3
12 + 3 = 15
