Question

The sum of the digits of a two-digit number is 12. The number obtained by interchanging the two digits exceeds the given number by 18. Find the number.

(A) 57 

(B) 75 

(C) 85 

(D) 58

Answer 1

The correct option is: (A) 57 

Explanation:

Let the unit's and ten's digits in the number be y and x respectively.

So, the number be 10x + y.

According to the question,

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

Also,10x + y +18 = 10y + x

=> 9x -9y =-18 = x - y =-2         ......(2)

Solving (1) and (2), we get x = 5 and y = 7

.'. Required number is 57.