Question

a number consists of two digits whose sum is 9 if 9 is subtracted from the number the digits interchange their places find the number

Answer 1

Thats 54
... hope it helps u...

Answer 2

x+y=9
10x+y-9=10y+x
9x-9y=9
x-y=1
x+y=9
2x=10
x=5
y=4
it means that the no. is 54