word problem

Question

The maximum weight that a rectangular beam can support varies jointly as its width and the square of its height and inversely as its length. If a beam one fourth
foot wide, one half
foot high, and 11 feet long can support 30 tons, find how much a similar beam can support if the beam is one fourth
foot wide, one third
foot high, and 13 feet long. 

Answer 1

The formula, as stated in words, becomes W = kwh²/L

 

The rest of your job is to substitute all of the givens and thus determine the value of k (constant of proportiolnality).

 

Finally, then, you can calculate W in the case where w=¼, h=1/3, L=13.