The total resistance of the combination is 650 + 350 + 1000 = 2000 ohms. This is because when resistances are connected in series, the resistance of the combination is equal to the sum of individual resistances. R = R1+ R2+ R3+ R4+....+ Rn where R is the total resistance and R1, R2, Rn etc are the individual resistances connected in series.
