Final answer:
Thomas' age is determined to be 9 years old by setting up a system of linear equations based on the given relationship that Huilan's age is three times Thomas' age and their combined ages total 36.
Step-by-step explanation:
The student is asking a mathematical problem involving the concept of linear equations. To find Thomas' age, we can set up two equations based on the information provided: Let's let T represent Thomas' age, so H represents Huilan's age which is three times Thomas' age (H = 3T). The sum of their ages is 36 (H + T = 36). Now we have two equations: 1) H = 3T and 2) H + T = 36. Solving this system of equations we substitute the first equation into the second, giving us 3T + T = 36 which simplifies to 4T = 36. Dividing both sides by 4 gives T = 9.
Therefore, Thomas' age is 9 years.