Section $6-3$ Ripple Carry and Look$-$Ahead Carry Adders

$11.$ Each of the eight full$-$adders in an $8-$bit parallel ripple carry adkler exhihits the following proput gation deisy:

$Ato$ and $C_{\text{o}\text{u}\text{r}\text{i}},20ns$

$Bto$ and $C_{\text{n}\text{u}\text{t}\text{i}},20ns$

$C_{in}to$:$,30ns$

$C_{in}to{C}_{\text{o}\text{u}\text{t}},25ns$