For the concrete beam shown $($Use fy $=60,000,Ec=4000$ksi, concrete unit weight $=0\mathrm{.}148\frac{k}{f}t3,$ sand

lightweight concrete$)$:

a$-$ Calculate concrete unit compressive strength and modulus of rupture in psi.

b$-$ Use concrete unit compressive strength from part $($a$)$ and calculate the maximum steel ratio.

c$-$ Use concrete unit compressive strength from part $($a$)$ and calculate the design moment strength.