Devaughn is 10 years older than sydney. the sum of their age is 64.what is sydney age?

Hello!

You can make this into two expressions based on what you know

let x stand for Devaughn's age
let y stand for Sydney's age

x = y + 10
x + y = 64

You can put x into the second equatoin

y + 10 + y = 64

Combine like terms

2y + 10 = 64

Subtract both sides by 10

2y = 54

Divide both sides by 2

y = 27

You can put y into the first equation

x = 27 + 10

combine like terms

x = 37

Devaugn is 37 and Sydney is 27

Hope this helps!

With a continuous thought process.