Final answer:
The number -1 1/19 is a rational number because it can be expressed as the improper fraction -18/19, which is a ratio of two integers.
Step-by-step explanation:
The number -1 1/19 is not an irrational number. An irrational number is a number that cannot be written as a simple fraction, meaning it cannot be represented as a ratio of two integers. However, the number you've provided, -1 1/19, is a mixed number and can be expressed as an improper fraction. Specifically, it is equal to -1 + 1/19, and when combined into a single fraction, it becomes -18/19 (because -1 is the same as -19/19, so -19/19 + 1/19 equals -18/19). This expression is a ratio of two integers, hence it is a rational number, not irrational.