Net cost of new machine with pro-rata depreciation Steps:

• Carrying value of old machine at exchange: $2500 (given, assuming at 30 June).
• Cost of new machine: cash paid $3000 + carrying value of old machine traded in$2500 = $5500 (standard part exchange accounting avoiding gain recognition).
• Depreciation on new machine: 20% per annum reducing balance, pro-rata for 6 months owned (30 June to 31 December) = $5500 × 20$550.
• Carrying value at 31 December: $5500 -$550 = $4950.

Not enough information (ambiguous trade-in valuation and prior depreciation on old machine; choices suggest possible other assets or different cost basis).

Final answer: Not enough information.