Question

Number Theory: The sum of a 2-digit number and the 2-digit number when the digits are reversed is 77. If the difference of the same two numbers is 45, what are the two 2-digit numbers?

Answer 1

Let x represent the first digit and y the second. Because of the way the decimal system works, the number can be expressed as:

10^1 * x + 10^0 * y = 10x + y

Then, the number reversed is:
10^1 * y + 10^0 * x = 10y + x

Add those two together and set it to 77, then subtract the two and set it to 45. Solve.

Answer 2

Um, I got 61 and 16?

Answer 3

61 + 16 = 77
61 - 16 = 45
Seems good.

Answer 4

thank you!
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