You have 30 customers in week 1, 55 in week 2, 80 in week 3, what would you project for week 4.

I did just basic math and came up with 105, but I think there is some kind of equation or formula that I need and just don't know what it is.

Just because there were 25 more customers than the week before during weeks 2 and 3 doesn't mean a thing for week 4. I suppose you could say 105 but I would just say 'meaningless problem.'

The estimate of 105 for week 4 is reasonable, as each week the attendance increases by 25. The formula is:

C = 30 + (25 x (n-1))

where n = week number 1, 2, 3 etc.

I live in a rural area where week 4 would probably plateau from lack of PEOPLE. If this is a math problem it should use a situation that isn't likely to do so.

I agree that this is a good example of a bad math problem. Common sense tells you that the scenario is bogus, and so the poor student spends more time being confused by a ridiculous scenario than actually learning and applying math concepts. Unfortunately this happens all the time, especially in elementary school, and I am certain that it is one of the reasons so many people find math "hard" and "confusing" - they fear that if the question makes no sense it must be that they are stupid and don't get it. I really wish the people who dream up these problems would think twice about whether it passes the common sense test.

Ok, rant mode off now :)

Thank you both for your help, I was just confused and yes questions should be a little less stupid.

Mr. ebaines, I love the formula and would like for you to walk me through it. I don't want you to do all of it just help show me how to work out this formula.

Guys it is 25 additional customers a week, it makes complete sense ( assuming you are thinking about 6th grade math.
My son does these types of questions all the time.

So the next week if you grow 25 customers all the weeks prior, you would assume you get another 25.

Not a business or marketing question, but a word math question.