The difference between a two-digit number and the number obtained after interchanging its two digits is 36. The sum of the two digits of the number is 12. Find the lowest such possible number.

• A. 49
• B. 47
• C. 50
• D. 48

Answer: (D)

Let the digits be x and yTherefore, x + y = 12 .............(1)(10y + x) - (10x + y)                    Therefore, y - x = 4............. (2)Solving (1) and (2), y = 8              Therefore, x = 4There are two possible numbers 48 and 84. So the lowest no. is 48.