Word equation, algebra

Question

The sum of two numbers is 30 and their difference is 10. What are the two numbers?

Answer 1

x+y = 30

x-y =10

2x =40

x =20

y = 10

the numbers are 10 and 20

or another method

30/2 = 15

to be 10 apart, add and subtract 10/2 =5

15+5 = 20

15-5 =10

Answer 2

If the numbers are x and y, then x and y = 30 and x- y = 10.

This is a system of equations that can be solved by the elimination method

x + y = 30

x - y = 10 by adding, you can eliminate the y term.

2x = 40, so x = 20. y = 30 - x, so y = 10.

Could you figured that out without algebra?