IlCreatore wrote:

We can translate what is written in formulas as \(s=\frac{t^3}{l^3}\) where s is stiffness, t is thickness and l is length. Then, if board A has 3 times the length and 8 times the stiffness of table B, the formula is rewritten as \(8s=\frac{t^3}{8*l^3}\) so that \(t^3=8s*8l^3\). Thus the ratio between the cubic thickness of the two tables is \(\frac{64sl^3}{sl^3}=64\) but since this is the cubic ratio we have to compute the cubic root to find the ratio between thickness, i.e. \(64^{\frac{1}{3}}=4\)

Can someone explain this to me? I am really struggling with this problem. I understand how you got to S = t^3/l*3, but I don't understand how you got to the next step. How did you end up with 8*l^3 in the denominator?

Thanks in advance.