Question

Exercise 5A
بل
The sum of the digits of a two-digit number is 15. The number obtained by interchanging it
digits exceeds the given number by 9. Find the original number.​

Answer 1

Given:-The sum of digits of a two digit number is 15

The number exceeds the given number by 9 when digits are interchanged. Let ten's place digit be x & one's place digit be y. x+y=15 - - - - - (I)

The number is:-

10x+y

When digits are interchanged

10y+x

According to the question :-

10x+y+9=10y+x

=>10x-x+y-10y=-9

=>9x-9y=-9

=>x-y=-9/9=-1 - - - - - (ii)

From eq (I) & eq (ii) we obtained that :-

2x=14

x=14/2

x=7

Substituting the value of x in eq (I) we obtain that :-

7+y=15

y=15-7

y=8

So, the number is 10x+y=10*7+8=70+8=78 (This is the required answer.) [If you liked my answer then please mark me as brainliest and I will definitely follow you back.]