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    Question

    If the total cost of 7 books and 5 pens is Rs. 350 and the

    total cost of 3 books and 2 pens is Rs. 160, then find the cost of 10 books.
    A Rs.1000 Correct Answer Incorrect Answer
    B Rs.2500 Correct Answer Incorrect Answer
    C Rs.1560 Correct Answer Incorrect Answer
    D Rs.1165 Correct Answer Incorrect Answer

    Solution

    ATQ,

    Let the cost of one book and one pen be Rs. x and Rs. y, respectively.

    ATQ;

    7x+5y=350........(I)

    3x+2y=160.......(II)

    Multiply Equation (II) by 5 and Equation (I) by 2, then subtract:

    (3x+2y)×5−(7x+5y)×2

    15x+10y−14x−10y=800−700

    x=100

    Cost of 10 books = 10×100=1000 Rs.

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