a) 5
b) 6
c) 7
d) 8
Answer: b
Explanation: Let the numbers are in the form of (10x + y), so when the digits of the number are reversed the number becomes (10y + x)
According to question,
(10y + x) – (10x + y) = 18
9(y – x) = 18
→ y – x = 2
So, the possible pairs of (x, y) are
(1, 3), (2, 4), (3, 5), (4, 6), (5, 7), (6, 8) and (7, 9)
we need the number other than 13.
There are 6 possible numbers i.e. 24, 35, 46, 57, 68, 79
So, total numbers of possible numbers are 6
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