In how many ways can you make 50 paise using only 10 paise and 5 paise coins (using at least one of each)?
- A.3
- B.4 ✓
- C.5
- D.6
Explanation: Solving 10a+5b=50 with a,b≥1: (a,b) = (1,8),(2,6),(3,4),(4,2) — 4 ways.
Class 6 IMO Mathematics Olympiad practice · Olympiad Thinking · Working Backwards & Problem-Solving Strategies
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