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Mathematical Puzzles Hard 3 min

A three-digit number has digits that add up to 15. The hundreds digit is twice the units digit, and the tens digit is 3 more than the units digit. What is the number?

Hint
Let the units digit be x.

Answer

663.

Explanation

Let the units digit be x. The hundreds digit is 2x and the tens digit is x+3. Therefore 2x + (x+3) + x = 15, giving 4x = 12 and x = 3. The number is 663.

Step-by-Step Solution

Units = x.
Hundreds = 2x.
Tens = x + 3.
2x + x + 3 + x = 15.
4x = 12.
x = 3.
Hundreds = 6, tens = 6, units = 3.
Answer = 663.
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