Question

The sum of a two digit number is17 and the difference between digits is one. What is that two digit number?

Answer 1

Answer:

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=99

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=182

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

Answer 2

98
9+8=179-8=1so seems that 98 could be the possible answer since adding the two digits will give you 17 and subtracting will give you one.