Question

The tens digit of a certain number is five more than the units digit. The sum of the digits is 9. Find the number.

Answer 1

the tens digit = n
the units digit = n-5

n + n-5 = 9
2n = 9+5
2n = 14
n = 7 ← the tens digit

the units digit = n-5 = 7 - 5 = 2

the number is 72

Answer 2

Answer: 72

Explanation:

Let x represents the units digit of the number, then the value of tens digit will be
`x+5`.

According to the question , we have the following equation:-

`\Rightarrow\ x+x+5=9\\\\\Rightarrow 2x+5=9`

Subtract 5 on both sides , we get

`2x=4`

Now, Divide 2 on the both sides , we get

`x=2`

Now, the unit digit of the number = 2

The tens digit of the number = 2+5=7

Then , the number will be : 72