Use the top-level ratio 7:3 to find how many engineers and designers there are, then break each group down using sub-ratios.
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• Top-level ratio 7:3 means 10 units in total.
• 120 ÷ 10 = 12 per unit.
• Engineers: 7 × 12 = 84
• Designers: 3 × 12 = 36
For the engineers (sub-ratio 5 + 2):
• 7 parts = 12 per part
• software: 5 × 12 = 60
• hardware: 2 × 12 = 24
For the designers (sub-ratio 2 + 1):
• 3 parts = 12 per part
• UX: 2 × 12 = 24
• graphic: 1 × 12 = 12
Total software: 60.
Check: 84 + 36 = 120 = total (120). ✓
Final Answer: 60