How do you make a function table? This is the question

Jackie is saving her money to buy a coat that costs $121. she already has $61 and if she saves $15 each week,in how many weeks can she buy coat? make a function table to answer the question.

I know the answer is four weeks but I don't know how to make a function table to solve it.

I need this before 5:00.

This site should help you.

http://www.ehow.com/about_5431722_math-function-table.html

thank you soo soo much

You're very welcome.

the function table on my homework has three columns instead of one so I don't understand it

I mean instead of two

4 weeks