Answer:
20 years old
Step-by-step explanation:
Joe = J
Sydney = S
J = 5 + S
J + S = 45
Substitute
5 + S + S = 45
Add
5 + 2S = 45
Subtract 5 from both sides of the equation
2S = 40
Divide both sides of the equation by 2
S = 20
Sydney is 20 years old
Hope this helps :)
