Q1.The sum of a two digit number and the number obtained by interchangeing it's digit is 99 . Find the number.
Answers
Explanation:
since, we don't know the numbers so,let us assume the ten's digit be 'x'
and unit digit be 'y'
Original number formed = 10x +y
Number formed after interchanging it's digit => 10y+x
according to the question:
sum of two digit numbers and the number obtained by interchanging it's digit is 99
then our Equation becomes
=> 10x+y+10y+x=99
=>11x+11y=99
=> 11(x+y)=99
=>x+y= 9
Since , we only obtained one Equation so,the numbers can be 18,81, 54,45,27,72,36,63 etc
CONCEPT:
the unit place must be greater than the ten's place only if our answer be correct.
let's take the number 18. Here, 8 -1 is 7, but 1-8 is - 7 also 8+1 is also 9 so the given answer is correct.
Answer:
Answer
Let the two digit number be 10x + y.
Number obtained on interchanging the digits = 10y + x.
The sum of a two digit number and the number obtained by interchanging its digits is 99.
10x + y + 10y + x = 99
⇒ 11x + 11y = 99
⇒ x + y = 9
With the given information, only one equation can be formed. So, the number can be 18, 81, 54, 45, 27, 72, 36, 63.