Rational number is a group of numbers that can be written as a ratio of two integers. Basically that means that rational numbers can also be written as fractions.
Speaking of decimals, decimal numbers can be rational if they have finite number of decimals (0.752). Ecception to this rule are repeating decimals numbers; decimal numbers which have infinitely many decimals but they repeat in a pattern (0.23232323...).
Now, knowing this, it's easy to answer the question.
There are three times as many teaching assistants as research assistants. Find the number of research assistants employed by the university. Hence the number of research assistants is 170.
