Question

Which of the following statements contain a variable? Check all that apply. A. There are 60 seconds in a minute. B. He is 15 years old. C. Double the number of pages in the book. D. The age of my friend.

Answer 1

The answer is the option C and the option D, which are:

C. Double the number of pages in the book.

D. The age of my friend.

The explanation for this problem is shown below:

By definition, a variable is an unkown quantity. In the Option A the quantity is given: $60$ seconds in a minute. In the option B you know the quantity too, which is $15$ years old. But the option C and the option D does not give any quantity, you don't know the number of pages in the book or the age of the friend yet. Therefore, the answer is the options C and D.