Use the top-level ratio 3:5 to find how many morning and evening classes there are, then break each group down using sub-ratios.
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• Top-level ratio 3:5 means 8 units in total.
• 144 ÷ 8 = 18 per unit.
• Morning: 3 × 18 = 54
• Evening classes: 5 × 18 = 90
For the morning (sub-ratio 7 + 2):
• 9 parts = 6 per part
• members: 7 × 6 = 42
• non-members: 2 × 6 = 12
For the evening classes (sub-ratio 3 + 2):
• 5 parts = 18 per part
• members: 3 × 18 = 54
• non-members: 2 × 18 = 36
Total non-members: 12 + 36 = 48.
Check: 54 + 90 = 144 = total (144). ✓
Final Answer: 48