Question

in a 2 digit number the units digit is twice the tens digit.if 27 is added to the number the digits interchange their places.find their number

Answer 1

Let the number be 10x+y
y=2x

Interchanged number= 10y+x
y=2x

12x+27=21x
27=9x
3=x

10(3)+6= 36
(y=2x)

Answer_ (36,63)