Give the step-by-step reasoning process and then the final answer. Cynthia has three children whose ages add up to 35. Matthew is two years older than Rebecca and four years younger than Freddy. How many years old is Freddy?
Let A be Matthew's age. Rebecca is A - 2 years old. Freddy is A + 4 years old. Their ages add up to 35, so A + A - 2 + A + 4 = 3A + 2 = 35. Therefore, 3A = 35 - 2 = 33. Matthew is A = 33 / 3 = 11 years old. Thus, Freddy is 11 + 4 = 15 years old.
The final answer: 15.