The rectangular hollow box beam in the figure has a concrete compressive strength of $4,000$ psi and is reinforced with Grade $60(f_y=60$ksi $)$ steel reinforcement. Compute the factored moment capacity $)$ and check for the following cases:

A$.$ The tension reinforcement is $(6)$ #$8$ bars. The area of a single #$8$ bar is $0\mathrm{.}79.($Hint: Assume the compression block lies completely within the top flange, i$.$e$.<mtext></mtext><mn>5</mn>$ in$).$

B$.$ The tension reinforcement is $(6)$ #$11$ bars. The area of each #$11$ bar is $1\mathrm{.}56($Hint: assume the compression block extends to the web of the beam, i$.$e$.>5$ in$)$