Use the top-level ratio 3:2 to find how many electronics and furniture there are, then break each group down using sub-ratios.
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• Top-level ratio 3:2 means 5 units in total.
• 180 ÷ 5 = 36 per unit.
• Electronics: 3 × 36 = 108
• Furniture: 2 × 36 = 72
For the electronics (sub-ratio 5 + 4):
• 9 parts = 12 per part
• imported: 5 × 12 = 60
• local: 4 × 12 = 48
For the furniture (sub-ratio 1 + 3):
• 4 parts = 18 per part
• imported: 1 × 18 = 18
• local: 3 × 18 = 54
Total imported: 60 + 18 = 78.
Total local: 48 + 54 = 102.
Ratio = 78:102 = 13:17.
Check: 108 + 72 = 180 = total (180). ✓
Final Answer: 13 : 17