In a two-digit number, the digit in unit's place is two more than three times the digit in ten's place. If the sum of the two digits is 10, what is the number ?

• A. 24
• B. 22
• C. 28
• D. 18

Answer: (C)

Let the number be 10x + y.∴ y = 3x + 2 .......(i)And, x + y = 10 ......(ii)From (i) and (ii), x = 2, y = 8∴ Number = 28