If 9-3=18, and 21-8= 39, then 7-4 =?
Show answer & explanation
Correct answer: C
Explanation
Logic: Answer = (First number − Second number) × 3
Check:
- 9 − 3 = 6 → 6 × 3 = 18 ✓
- 21 − 8 = 13 → 13 × 3 = 39 ✓
Apply to 7 − 4:
7 − 4 = 3 → 3 × 3 = 9
Answer: 9