Word Problems :(

[Dinky_Bell]

Ok I'm generally good when it comes to math...but word problems just aren't my thing, so if anyone can help me or give me an idea as to what to do it would be a big help.


31. A group of friends rent a house at the beach for spring break. If nine of them share the house, it costs $150 each. Is the cost to each person directly or iversely prportional to the number of people sharing the house? Explain you reasoning and write a formula for the proportion. How many people are needed to share the house if each student wants to pay a maximun of $100 each? :?:


*Its inversely proportional because the cost incereases when the # of ppl decreases and visa versa...but thats as far as i got...the whole 'equation out of a word problem' thing is what gets me. :?

Please help...oh the inverse equation is y=k/(x^n)...thankx

 

[Gene]

The key sentence is

If nine of them share the house, it costs $150 each.

Inversly proportinal says the equation is y=k/x, (not x^2 nor x^3). Proportional means if one doubles the other halves. You could say something varies inversly with x^2 but that isn't proportinal.
So you have
150 = k/9
Not too mind-boggling, is it?
Find k, then it becomes
100 = 9*150/x