Puzzle No.59 Solution

The number is 54, simply because
54 = 6 (5 + 4).

Algebraic solution:

Let t be the digit in the tens place and u be the digit in the units place. Then, the number is 10 t + u, and the sum of its digits is t + u. The following equation can be readily written:

10 t + u = 6 t + 6 u or
4 t = 5 u.

Thus, t / u = 5 / 4. Since t and u are digits, t must be 5 and u must be 4.

Puzzle No.59/Solution
Unique Numbers
The number is 54, simply because 54 = 6 (5 + 4). Algebraic solution: Let t be the digit in the tens place and u be the digit in the units place. Then, the number is 10 t + u, and the sum of its digits is t + u. The following equation can be readily written: 10 t + u = 6 t + 6 u or 4 t = 5 u. Thus, t / u = 5 / 4. Since t and u are digits, t must be 5 and u must be 4.