Deepak bought 3 notebooks and 2 pens for Rs. 80. His friend Ram said that price of each notebook could be Rs. 25. Then three notebooks would cost Rs.75, the two pens would cost Rs.5 and each pen could be for Rs. 2.50. Another friend Ajay felt that Rs2.50 for one pen was too little. It should be at least Rs. 16. Then the price of each notebook would also be Rs.16. Lohith also bought the same types of notebooks and pens as Aditya. He paid 110 for 4 notebooks and 3 pens. Later, Deepak guess the cost of one pen is Rs. 10 and Lohith guess the cost of one notebook is Rs. 30.
1. Form the pair of linear equation in two variable from the situation by taking cost of 1 notebook as rupees X and cost of one pen is rupees y
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Answer:
(i) (a) (ii) (a) (iii) (b) (iv) (d) (v) (a)
Step-by-step explanation:
(ii) 3x + 2y = 80 . . . . .(1)
4x + 3y = 110 . . . . . .(2)
(1) x 3 - (2) x 2
9x + 6 y = 240
8x + 6 y = 220
x = 20 Rs cost of one note book
From (1) 2y = 80 - 60 = 20 ⇒ y = 10 Rs. cost of one pen
iv) 15x + 12y = 15 x 20 + 12 x 10 = 300 + 120 = 420 Rs
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