Question

one of the two digits of a digit number is twice the other digit .if you interchanges the digits and add the resulting number to the original number ,you get 33 .what is original number?​

Answer 1

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Let the original number be xy.

Put, x at tens place

y at ones place.

According to the question,

One of the two digits of a digit number is twice the other digit .

y = 2x ----(1)

Case 1 :-

For original ,

x at tens place

y at ones place. ➝ 2x

Original number =

10 (tens) + 1 (ones)

➝ 10(x) + 1(2x)

➝ 10x + 2x

➝ 12x

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Interchanging the digits

Case 2 :-

For reversal ,

y at tend place. ➝ 2x

x at ones place

Reversing number =

10 (tens) + 1 (ones)

➝ 10(2x) + 1(x)

➝ 20x + x

➝ 21x

Adding the resulting number to the original number we get 33 .

12x + 21x = 33

➝ 33x = 33

➝ x = 33/33

➝ x = 1

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x at tens place = 1

y at ones place. ➝ 2x = 2×1

The original number will be 21 .