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.

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: seconds in a minute. In the option B you know the quantity too, which is 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.

  the correct choice is marked

step-by-step explanation:

the first two graphs show multiple turning points. the last graphs matches the description in every detail.

step-by-step explanation: