Answer:
Simone is 16 and Olivia 12 years old.
Explanation:
"Simone is four years older than her sister Olivia."
(1) Simone age = Olivia age + 4
"Their combined ages is 28."
(2) Simone age + Olivia age = 28
→ We can substitute from the first equation (1) Simone age with Olivia age + 4 into the second equation (2)
Simone age + Olivia age = 28
Olivia age + 4 + Olivia age = 28, subtract 4 from both sides
Olivia age -4 +4 + Olivia age = 28 - 4
2· Olivia age = 24 , divide both sides by 2
Olivia age = 24/2
Olivia age = 12 years old
→ From the first equation (1) we have:
Simone Age = Olivia age + 4 = 12 + 4 = 16 years old
Check our answer:
"Their combined ages is 28 "
12 + 16 = 28 ✅