A shopkeeper has 3 varities of pens ‘A’, ‘B’ and ‘C’. Meenu purchased 1 pen of each variety for a total of ₹21. Jeen purchased 4 pens of ‘A’ variety, 3 pens of ‘B’ variety and 2 pens of ‘C’ variety for ₹60. While Shikha purchased 6 pens of ‘A’ variety, 2 pens of ‘B’ variety and 3 pens of ‘C’ variety for ₹70. Using matrix method find the cost of each pen.

Matching exercise

    
Match the items on the right to the items on the left.
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Let the varieties of pen A, B and C be x, y and z respectively. As per the Data we get,
x + y + z = 21
4x + 3y + 2z = 60
6x + 2y + 3z = 70
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|A| = 1(9 – 4) – 1(12 – 12) + 1(8 – 18)= – 5
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