A shopkeeper in Delhi sells 3 pens and 4 pencils for ₹25. He also sells 4 pens and 3 pencils for ₹24. Using determinants, what is the cost of one pen?
A shopkeeper in Delhi sells 3 pens and 4 pencils for ₹25. He also sells 4 pens and 3 pencils for ₹24. Using determinants, what is the cost of one pen?
- A. ₹3
- B. ₹4
- C. ₹2
- D. ₹5
Answer: A) ₹3
Explanation: Equations: 3x+4y=25 and 4x+3y=24. D = 9-16 = -7. Dx = 25(3)-24(4) = 75-96 = -21. x = -21/-7 = ₹3.
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