The sum of the in a two digit number is 17. lf the digits are reversed, the new digits number will be 9 less than the original number. What is the original number?

1 Answer
Oct 4, 2016

The number is 98

Explanation:

Let the number be 10x+y

So we can write

x+y=17------------------------------Eq 1

Reverse of the number will be 10y+x

So we can write

(10x+y)-(10y+x)=9

or

9x-9y=9

or

9(x-y)=9

or

x-y=9/9

or

x-y=1-------------------Eq 2

Adding up the Eq 1 and Eq 2

we get

x+y+x-y=17+1

or

2x+0=18

or

2x=18

or

x=18/2

or

x=9

By plugging the value x=9 in the x+y=17

We get

9+y=17

or

y=17-9

or

y=8

Therefore the number is 98