Need Help on problem. ITs confusing to me..

[chilledsoup]

Stairs are designed according to the following principle: The normal pace length is 60 cm. This must be decreased by 2 cm for every 1 cm that a person's foot is raised when climbing stairs. According to this design, how should the "thread length" depend upon the height of each "riser"?

 

[stapel]

If the stair rises one centimeter, what is the width of the step? (I am assuming that the undefined term "thread length" refers to the width of the step.) If the stair rises two centimeters, what is the width of the step? If the stair rises three centimeters, what is the width of the step?

Continue, until you note a pattern in what you're doing. Once you do find the pattern, write an expression for the width when the stair rises "x" centimeters.

Eliz.