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A two-digit number has digits whose sum is 9. Reversing the digits decreases the number by 27. Find the number.
A54
B63
C36
D72
Answer & Solution
Correct answer: B. 63
Let digits be a (tens) and b (units). Number = 10a + b. Conditions: a + b = 9 and (10a + b) − (10b + a) = 27 ⇒ 9(a − b) = 27 ⇒ a − b = 3. Solve: a = 6, b = 3. Number = 63.
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