Q. A number of two digits has the sum of its digits as 7. When 9 is subtracted from the number, digits are reversed. The number is

Question

Q. A number of two digits has the sum of its digits as 7. When 9 is subtracted from the number, digits are reversed. The number is

in progress 0
Valentina 2 months 2021-08-13T00:21:04+00:00 1 Answer 0 views 0

Answers ( )

    0
    2021-08-13T00:22:25+00:00

    EXPLANATION.

    • GIVEN

    a number of two digit has the sum of its digit

    as = 7

    when 9 is subtracted from the number, digit

    are reversed.

    TO FIND THE NUMBER.

    According to the question,

    Let the tens place = x

    Let the unit place = y

    original number = 10x + y

    reversing number = 10y + x

    Conditions = 1

    A number of two digit has the sum of its

    digit = 7

    => x + y = 7 ……..(1)

    Conditions = 2

    when 9 us subtracted from the number, digit

    are reversed.

    => 10x + y – 9 = 10y + x

    => 9x – 9y = 9

    => x – y = 1 ……..(2)

    From equation (1) and (2) we get,

    => 2x = 8

    => x = 4

    put the value of x = 4 in equation (1)

    we get,

    => 4 + y = 7

    => y = 3

    Therefore,

    Number are = 10x + y

    => 10(4) + 3 = 43

    Number are = 43

Leave an answer

Browse
Browse

18:9+8+9*3-7:3-1*13 = ? ( )