Jack bought 7 tickets for a movie. He paid $7 for each adult ticket and $4 for each child ticket. Ja

Discussion in 'Calculator Requests' started by math_celebrity, Dec 16, 2016.

  1. math_celebrity

    math_celebrity Administrator Staff Member

    Jack bought 7 tickets for a movie. He paid $7 for each adult ticket and $4 for each child ticket. Jack spent $40 for the tickets

    Let a = Number of adult tickets and c be the number of child tickets.

    1. 7a + 4c = 40
    2. a + c = 7
    3. Rearrange (2): a = 7 - c
    Now substitute a in (3) into (1):
    7(7 - c) + 4c = 40
    49 - 7c + 4c = 40
    49 - 3c = 40

    Add 3c to each side and subtract 40:
    3c = 9

    Divide each side by 3:
    c = 3

    Substitute c = 3 into Equation (2)
    a + 3 = 7

    Subtract 3 from each side:
    a = 4
     

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