The sum of the digits of a 2-digit number is 9. The number is 6 times the units digit. find the number.

Question

The sum of the digits of a 2-digit number is 9. The number is 6 times the units digit. find the number.

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Natalia 1 week 2021-09-13T23:52:35+00:00 1 Answer 0 views 0

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    2021-09-13T23:53:54+00:00

    The digit in the tens place is x

    The digit in the ones place is y

    The number is (10x + y)

    Form equation 1 :

    THE sum of the digits is 9

    x + y = 9

    x = 9 – y

    Form equation 2 :

    The number is 6 times the units

    10x + y = 6y

    Put the two equations together:

    x = 9 – y ——————– [ 1 ]

    10x + y = 6y ——————– [ 2 ]

    Find y:

    Sub [ 1 ] into [ 2 ]:

    10(9 – y) + y = 6y

    90 – 10y + y = 6y

    90 – 9y = 6y

    15y = 90

    y = 90 รทย 15

    y = 6

    Find x:

    When y = 6

    x = 9 – 6

    x = 3

    Find the number

    The number = 10x + y

    The number = 10(3) + 6

    The number = 36

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