7. A number consists of two digits whose sum is 12. If 18 is added to the number, the digits are

reversed. Find the number.

Asked by Mn2790976 | 19th May, 2022, 09:45: AM

Expert Answer:

Let the digit at the tens place be x and the digit at the unit place be y. 

x+y=12  .........(1)

Required Number = (10x+y).

Number obtained on reversing the digits = (10y+x).

According to the condition, we get

(10y+x)−(10x+y)=18

→ 9y−9x=18

→   y−x=2     ..........(2)

Adding (1) and (2), we get

2y=14 y=7

 → x= 12 - 7 = 5

Hence, the required number is 57.

Answered by Renu Varma | 19th May, 2022, 04:14: PM