A store sells small notebooks for $6 and large notebooks for $12. If a student buys 6 notebooks and

Discussion in 'Calculator Requests' started by math_celebrity, Jun 10, 2020.

  1. math_celebrity

    math_celebrity Administrator Staff Member

    A store sells small notebooks for $6 and large notebooks for $12. If a student buys 6 notebooks and spends $60, how many of each did he buy?

    Let the amount of small notebooks be s. Let the amount of large notebooks be l. We're given two equations:
    1. l + s = 6
    2. 12l + 6s = 60
    Multiply equation (1) by -6
    1. -6l - 6s = -36
    2. 12l + 6s = 60
    Now add equation 1 to equation 2:
    12l - 6l + 6s - 6s = 60 - 36

    Cancel the 6s terms, and we get:
    6l = 24

    To solve for l, we type this equation into our search engine and we get:
    l = 4

    Now substitute this into equation 1:
    4 + s = 6

    To solve for s, we type this equation into our search engine and we get:
    s = 2
     

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