When two resistors of  (800±8) ohm and (600±6)  ohm are connected in parallel, value of the equivalent resistance is

1R=1R1+1R2⇒R=R1R2R1+R2R=800×600800+600=4800001400=343 Ω ΔRR2=∆R1R12+∆R2R22 ∆R3432=88002+66002 ∆R=3.43 ∆RR×100=3.43343×100=1%Equivalent resistance=343±1%