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A number consists of two digits. The sum of the digits is 9. If 63 is subtracted from the number, its digits are interchanged. Find the number. |
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Answer» Let the ten's digit be x. Then, unit's digit = (9 - x). Number = 10x + (9 - x) = 9x + 9. Number obtained by reversing the digits = 10 (9 - x) + x = 90 - 9x. therefore, (9x + 9) - 63 = 90 - 9x => 18x = 144 => x = 8. So, ten's digit = 8 and unit's digit = 1. Hence, the required number is 81. |
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