Use the top-level ratio 9:5 to work with 14 parts in total (no absolute total is needed for percentage). Then find how many parts represent learners who pass on the first attempt.
[[model:questions/solutions/q10480.png]]
• Top-level ratio 9:5 means 14 total parts.
• Automatic learners: 9 parts, Manual learners: 5 parts.
For the automatic learners (pass : don't pass = 5:4):
• 5 + 4 = 9 sub-parts matching the 9 parts above
• Pass: (5/9) × 9 = 5 parts
• Don't pass: (4/9) × 9 = 4 parts
For the manual learners (pass : don't pass = 2:3):
• 2 + 3 = 5 sub-parts matching the 5 parts above
• Pass: (2/5) × 5 = 2 parts
• Don't pass: (3/5) × 5 = 3 parts
Total parts who pass = 5 + 2 = 7 out of 14.
Percentage = 7/14 × 100% = 50%.
Check: 7 pass + 7 don't pass = 14 total parts. ✓
Final Answer: 50%