Question

I have 5 problems I seem to not be able to comprehend out of 150 that are due Tuesday. I have tried every which way to solve them on my own..please help.

Find the variation constant in which y varies inversely as x, and the following condition exists.

Y=30 when x = 1/6

k will = ____.

============================
The strength S of a rectangle beam varies jointly as its width w and the square of its thickness t.
If a wood beam 6 inches wide and 5 inches thick supports 500 pounds, how much can a similar beam 6 inches wide and 3 inches thick support? Round to the nearest pound if needed.

Thank you ahead of time for any consideration .

Answer 1

since y varies inversely as x, xy=k, a constant

1/6 * 30 = k
5 = k
-------------------------

S(w,t) = kwt^2
500 = k*6*25
500 = 150k
k=4

So, now we know k, and we can figure S from any w and t:

S(6,3) = 4*6*9 = 216