Question

The tens digit is three less than the units digit. If the digits are reversed, the sum of the reversed number and the original number is 121. Find the original number.

Answer 1

$\huge\sf\pink{Answer}$

☞ Original Number formed will be 47

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$\huge\sf\blue{Given}$

➝ The tens digit is 3 less than the units digit

➝ If the digits are reversed, then the sum of the original number and the reversed Number is 121

$\rule{110}1$

$\huge\sf\gray{To \:Find}$

✭ The original number?

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$\huge\sf\purple{Steps}$

Let the Ones Digit be a, and Tens Digit be (a - 3) of the Original Number.

✪ Original Number : 10(a - 3) + a

✪ Reverse Number : 10a + (a - 3)

❍ $\underline{\sf{As \: per\:the\: Question :}}$

$\dashrightarrow\sf\:\: Original\:No.+Reverse\:No.=121\\\\\dashrightarrow\sf\:\:[10(a-3)+a]+[10a+(a-3)]=121\\\\\dashrightarrow\sf\:\:10a - 30 + a + 10a + a - 3 = 121\\\\\dashrightarrow\sf\:\:22a - 33 = 121\\\\\dashrightarrow\sf\:\:22a = 121 + 33\\\\\dashrightarrow\sf\:\:22a = 154\\\\\dashrightarrow\sf\:\:a = \dfrac{154}{22}\\\\\color{lime}{\dashrightarrow\sf\:\:a = 7}$

❍ $\underline{\textsf{Original \ Number \ Formed :}}$

$\twoheadrightarrow\sf Original\:Number=[10(a-3)+a]\\\\ \twoheadrightarrow\sf Original\:Number=[10(7-3)+7]\\\\ \twoheadrightarrow\sf Original\:Number=[10(4)+7]\\\\ \twoheadrightarrow\sf Original\:Number=40+7\\\\ \color{aqua}{\twoheadrightarrow{\sf Original\:Number=47}}$

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Answer 2

hi QUEEN SP AKKA

let the tenth digit be X and unit digit be X+3 hence

the original no is 10(X)+X+3-----(1)

and reversed no is 10(X+3)+x-----(2)

adding 1 and 2

22x+33=121

22x=88

x=4

org no is 47