Final answer:
The smallest resistance obtainable by combining six 2.8 kΩ resistors in parallel is 467 Ω.
Step-by-step explanation:
The smallest resistance you can make by combining six 2.8 kΩ resistors is achieved by connecting them all in parallel. When resistors are connected in parallel, the total or equivalent resistance decreases and is found by the reciprocal formula: 1/R_total = 1/R1 + 1/R2 + ... + 1/Rn. For six identical resistors, this becomes 1/R_total = 6/R, where R is the resistance of one resistor. Substituting the value of 2.8 kΩ for each, you find that the smallest resistance is R_total = R/6. Therefore, the smallest resistance you can obtain with six 2.8 kΩ resistors in parallel is 2.8 kΩ / 6 = 0.467 kΩ, or 467 Ω.