Question:
When you reverse the digits of the number 13, the number increases by 18. How many other two-digit numbers increase by 18 when their digits are reversed?
When you reverse the digits of the number 13, the number increases by 18. How many other two-digit numbers increase by 18 when their digits are reversed?
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Digit reversal problems reduce to linear conditions on digit differences.
Updated On: Jul 31, 2025
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Verified By Collegedunia
The Correct Option is B
Solution and Explanation
Let number = $10a + b$, reverse = $10b + a$. Difference: $(10b + a) - (10a + b) = 9(b-a) = 18 \Rightarrow b-a = 2$.
$a$ can range from 1 to 7 (since $b \leq 9$), excluding $a=1$ for given 13 leaves 6 others.
\[
\boxed{6}
\]
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