A shopkeeper sold 3/5 of his stock on Monday and 40 items on Tuesday, leaving 20 items unsold. How many items did he originally have?
- A.130
- B.140
- C.150 ✓
- D.160
Explanation: After Monday, 2T/5 remained. Subtracting Tuesday's 40 leaves 20: 2T/5−40=20 → 2T/5=60 → T=150.
Class 6 IMO Mathematics Olympiad practice · Olympiad Thinking · Working Backwards & Problem-Solving Strategies
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