Let x is partial pressure of A and y is partial pressure of C when both equilibrium simultaneously established in a vessel
X(s)⇌A(g)+2B(g)
x (2x+2y);
KP1=PA×P2B(total)
Y(s)⇌C(g)+2B(g)
y (2y+2x);
KP2=PC×P2B(total)
KP1KP2=xy⇒x=2y
KP1=x(2x+2y)2
⇒x=0.1 atm;
∴ y=0.05 atm
Total pressure of gases =PA+PB+PC
=3(x+y)
=0.45 atm