Question

a number consists of two digits whose sum is 9 .if 27 is subtracted from the number its digits are reversed .find the number

Answer 1

let no.. be x and y
original no.. 10x+y
reversed no... 10y+x
acc too que
x+ y =9... eq 1
and 10 x+ y -27= 10y +x
9x-9y=27
x-y =3... eq 2
on add eq 1 and eq 2
x+y= 9
x-y = 3
2x=12
x=6
put the value of x in eq 1
x+y=9
y= 9- 6
y=3
so
original no...
10x+y
10×6+ 3
63

Answer 2

heya!!


==========================================

Let the unit's digit of the number be 'x'.


thus,A/Q,

=>ten's digit + one's digit = 9

=> ten's digit + x = 9

=>ten's digit = 9 - x

now,original number = 10(ten's digit) + 1 × unit's digit)

=10(9 - x) + x

= 90 -10x + x

=90-9x

and,reversed number = 10(one's digit) + 1 × ten's digit

=10(x)+ 9 - x

=10x + 9 - x

=9x + 9



According to the question,


original number - 27 = reversed number


=>90 - 9x - 27 = 9 x + 9


=>54 = 18x

=>x = 3

so,original number = 90 - 9x

= 90 - 9 × 3

=90 - 27

=63 Ans.


===============================
THANKS

@EVERkshitijEST