Question

the sum of digits of a two digit number is 9.if 63 is subtracted from the number,the digits interchange their places.find the number

Answer 1

Step-by-step explanation:

x+y=9

y =9-x

let the no be 10x+y

atp

10x+y -63 =10y+x

10x-x +y -9y =63

9x -9y =63

9y-9x= -63

9(9-x) -9x =-63

81-9x-9x=-63

-18x= -63-81

-18x= -144

x=8

y= 9-8=1

hence the no is 81

hope it helps