Question

The sum of the digits of a two digits number is 15 .The number obtained by interchanging the digits exceeds the given number by 9.The number is​

Answer 1

Answer:

78

Step-by-step explanation:

let the digit in units place be x and the digit in tens place be y.

then,the original number is 10y+x

the number obtained by interchanging digits=10x+y

cond. 1:

given,sum of digits=15

⇒ x+y=15    ---------- (1)

cond.2:

10x+y=10y+x+9

9x-9y=9

x-y=1  -------------- (2)

solving (1) and (2),  [by elimination method]

 x+y=15  

 x-y=1

-  +  -

--------------

 2y=14

y=7

put y=7 in (1),

x=15-7=8

hence,the given number=10y+x=78