For the conditions in problem $1$ above $($again conservatively designed$),$ suppose a rigid pavement was designed with a $12$ in slab $($modulus of rupture of $900$ psi, modulus of elasticity of $6\mathrm{.}0*106$ psi, load transfer coefficient of $3\mathrm{.}2,$ and drainage coefficient of $1\mathrm{.}0)$ for the four lane north bound direction described in problem $1($all other traffic and PSI information is the same as in that problem$).$ How confident would you be that this rigid pavement would have a PSI above $2\mathrm{.}5$ after $20$ years?P