How can I multiply a improper fraction to a whole number?

Here is the equation in my book. Y = 7 and X = 3. y/x • 3. The answer on the back of the book says 7, so I first multiplied the numerator(7) by 3 and divided that answer (27) by the denominator (3), and thats the only way I got 7.. but is that the right way? I can't find an answer on google that works :/. & sorry for adding the variables if they werent neccesary, i just wrote it exactly how it is in the book. Plese help.