Question

the sum of the digit of two digit number is 15.the no decrease by 27 if the digit are reversed. find the number

Answer 1

hey buddy here is your answer...

Let no. at ten’s place is x

and at unit place is y

also x+y=15

when position of numbers is reversed then original number becomes

27 less than new number therefore 10y+x=10x+y+27

9y-9x=27

y-x=3 also

x+y=15

adding we get 2y=18 or y=9

therefore x=15-9=6

hence required digit is= 69

Answer 2

Hi there!
Here's the answer:

•°•°•°•°•°<><><<><>><><>°•°•°•°•°

In two digit No.,
Let Units digit be x
& tens digit be 15 - x
(°•° given that sum of digits = 15)

No. = (10 × face value of tens place digit) + (1 × face value of units digit)

•°• Original No. = 10(15-x) + x

If the digits are reversed, Need No. is formed

New No. = 10(x) + (15-x)

Given that,
New No. = Original No. - 27
=> 10x + (15 - x) = [10(15 - x) + x] - 27
=> 9x + 15 = 150 - 10x + x - 27
=> 9x + 15 = -9x + 123
=> 18x = 123 - 15
=> 18x = 108
=> x = 6


•°• Unit digit of No. = x = 6
& tens digit of the no. = 15-x = 15-6 = 9


•°• Required No. = 96

•°•°•°•°•°<><><<><>><><>°•°•°•°•°

Verification:
No. = 96
•Sum of digits = 15

Digits are reversed
New No. = 69

Original No. - 27 = New No.
=> 96 - 27 = 69
•°• Given Data Matched

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Hope it helps