Question

The sum of digits of a two digit number is 12. If the number is increased by 18, its digit gets reversed. The number isggf

Answer 1

Explanation:

EXPLANATION.

Let the digit at tens place be = x

Let the digit at unit place be = y

Original number = 10x + y

reversing number = 10y + x

The sum of digit of a two digit number = 12.

=> x + y = 12 .......(1)

If the number is increased by 18 it's digit reversed.

=> 10y + x = 10x + y + 18

=> 9y - 9x = 18

=> y - x = 2 .......(2)

From equation (1) and (2) we get,

=> 2y = 14

=> y = 7

Put the value of y = 7 in equation (1) we get,

=> x + 7 = 12

=> x = 5

Therefore,

original number = 10x + y = 10(5) + 7 = 57.

Answer 2

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

original no. = 10x+y

reversed no.= 10y+x

a/q from 1st part--

x+y=12. ---(i)

a/q from 2nd part

10x+y+18=10y+x

9x-9y= -18

x-y= -2. -----(ii)

adding eq i and ii

2x=10

x=5

putting x=5 in eq i

5+y=12

y= 7