$C_{11}{H}_{24}$  has three quaternary and $x$ primary carbons. Thus, $x$  is…..

$C_{11}{H}_{24}$  (alkane) has three, quaternary C-atoms, thus each C-atom is attached to four C-atoms.

Thus, $C_{11}{H}_{22}$ has structure :

Total eight$1^0$ carbons