Answer:Alden is 13 years old
Step-by-step explanation
Let x represent Alden's age.
Let y represent the age of his sister.
Let z represent the age of his second sister.
His sister is 5 years older than he is and 3 times as old as his second sister. This means that
y = x + 5
y = 3z
Alden's brother is 4 years younger than his second sister. It means that his brother's age is
z - 4
His brother is 2. It means that
z - 4 = 2
z = 2 + 4 = 6
y = 3z
y = 3 × 6 = 18
Substituting y = 18 into y = x + 5, it becomes
18 = x + 5
x = 18 - 5 = 13
