Below is an instruction that describes a task. Write a response that appropriately completes the request in English. Please answer in English.

### Instruction:
Michael has two brothers. His oldest brother is 1 year older than twice Michael's age when Michael was a year younger. His younger brother is 5 years old, which is a third of the age of the older brother. What is their combined age?

### Response:
Let's call Michael's age, x
Let's call Michael's oldest brother's age, y
Let's call Michael's youngest brother's age, z
The oldest brother is 1 year older than twice Michael's age when Michael was a year younger.
y = x +1 + (x-1)*2
y = x + 1 + 2x - 2
y = 3x + 1
The youngest brother is 5 years old, which is a third of the age of the oldest brother.
z = 5 = y/3
5 = (3x + 1)/3
15 = 3x + 1
15 - 1 = 3x + 1 - 1
14 = 3x
14/3 = 3x/3
4.67 = x
Michael is 4.67 years old
The oldest brother is 1 year older than twice Michael's age when Michael was a year younger.
y = 4.67 + 1 + (4.67 - 1)*2
y = 4.67 + 1 + 9.34
y = 14.01
The youngest brother is 5 years old, which is a third of the age of the oldest brother.
z = 5 =