2 numbers add to 200. The first is 20 less than the second.

Discussion in 'Calculator Requests' started by math_celebrity, Jun 23, 2019.

  1. math_celebrity

    math_celebrity Administrator Staff Member

    2 numbers add to 200. The first is 20 less than the second.

    Let the first number be x and the second number be y. We're given:
    1. x + y = 200
    2. x = y - 20
    Plug (2) into (1)
    (y - 20) + y = 200

    Group like terms:
    2y - 20 = 200

    Typing this equation into our search engine, we get:
    y = 110 <-- This is the larger number

    Plug y = 110 into Equation (2) to get the smaller number:
    x = 110 - 20
    x = 90 <-- This is the smaller number

    Let's check our work for Equation (1) using x = 90, and y = 110
    90 + 110 ? 200
    200 = 200 <-- Good, our solutions check out for equation (1)

    Let's check our work for Equation (2) using x = 90, and y = 110
    90 = 110 - 20
    90 = 90 <-- Good, our solutions check out for equation (2)
     

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