"Since P,Q and R resistances are parallel,their equivalent is : "
1/M=1/2+1/3+1/6
1/M=(3+2+1)/6
1/M=6/6
1/M=1
M=1Omega
M("equivalent resistance of P,Q,R")
"Since The circuit current does not pass ,the resistance S does not affect the equivalent resistance."
"The equivalent resistance is 1"Omega