Question

the digits of two digit number differ by 3 if the digits are interchanged the resulting number is added to the original number we get 121 find the original number

Answer 1

the ans is In photo

Answer 2

Let the number be xy
xy=10x+y
x-y=3 eq 1
On interchanging the digits :
Number =yx= 10y+x

xy +yx =121
10x+y+10y+x=121
11x+11y=121
x+y=11. eq 2

Adding eq 1 and eq 2
2x = 14
x=7

Putting value of x in eq 1
x -y =3
7 -y=3
7 -3 =y
y=4

Number=xy=74