QUESTION $1$

Using the ACI Code requirements, calculate the design moment strength of a rectangular section that has a width of $b=250mm(10$ in $.)$ and an effective depth of $d=550mm(22$in$.)$ when $f_c^{\text{'}}=20$MPa$(3$ksi$),f_y=420$MPa$(60$ksi$),$ and the steel used is as follows:

a$)2$ #$9$ rebars

b$)3$ #$6$ rebars