Use the top-level ratio 2:7 to find how many donors and volunteers there are, then break each group down using sub-ratios.
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• Top-level ratio 2:7 means 9 units in total.
• 126 ÷ 9 = 14 per unit.
• Donors: 2 × 14 = 28
• Volunteers: 7 × 14 = 98
For the donors (sub-ratio 1 + 3):
• 4 parts = 7 per part
• corporate: 1 × 7 = 7
• individual: 3 × 7 = 21
For the volunteers (sub-ratio 2 + 5):
• 7 parts = 14 per part
• corporate: 2 × 14 = 28
• individual: 5 × 14 = 70
Total corporate: 7 + 28 = 35.
Total individual: 21 + 70 = 91.
Ratio = 35:91 = 5:13.
Check: 28 + 98 = 126 = total (126). ✓
Final Answer: 5 : 13