The sum of a two-digit number and the number obtained by reversing its digits is 132. If the digits differ by 2, find the number.

Answer: The number is 75 or 57.

Step-by-step solution

Step 1: Set up expressions for the numbers

Let the tens digit be xx and the units digit be yy. The original two-digit number is 10x+y10x + y. When the digits are reversed, the new number formed is 10y+x10y + x.

Step 2: Form the first linear equation

We are given that the sum of the original number and the reversed number is 132. Combining like terms gives 11x+11y=13211x + 11y = 132. Dividing both sides by 11 yields x+y=12x + y = 12.

Step 3: Account for both cases of the digit difference

Since the problem states that the digits differ by 2 without specifying which digit is greater, we must consider two cases: xy=2x - y = 2 or yx=2y - x = 2.

Step 4: Solve Case 1 where xy=2x - y = 2

Adding x+y=12x + y = 12 and xy=2x - y = 2 eliminates yy, giving 2x=142x = 14, so x=7x = 7. Substituting x=7x = 7 into x+y=12x + y = 12 gives y=5y = 5. Thus, the original number is 75.

Step 5: Solve Case 2 where yx=2y - x = 2

Adding x+y=12x + y = 12 and yx=2y - x = 2 eliminates xx, giving 2y=142y = 14, so y=7y = 7. Substituting y=7y = 7 into x+y=12x + y = 12 gives x=5x = 5. Thus, the original number is 57.

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