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प्रश्न
A number consists of two digits whose sum is 10. If 18 is subtracted form the number, its digits are reversed. Find the number.
उत्तर
Let the ones digit and tens digit be x and y respectively.
Then as per the question
x + y = 10 …….(i)
(10y + x) – 18 = 10x + y
x –y = -2 …….(ii)
Adding (i) and (ii), we get
2x = 8 ⇒ x = 4
Now, putting x = 4 in (i), we have
4 + y = 10 ⇒ y = 6
Hence, the number is 64.
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