A) 25
B) 72
C) 63
D) 36
Correct Answer: D
Solution :
[d] Let unit digit and ten's digit are y and x respectively. |
By condition, \[x+y=9\] ...(1) |
and \[(10x+y)+27=10y+x\] |
\[\Rightarrow \,\,\,\,\,\,\,\,\,\,\,\,9y-9x=27\] |
\[\Rightarrow \,\,\,\,\,\,\,\,\,\,\,\,y-x=3\] .(2) |
From eqs. (1) and (2), we get |
\[y=6\] and \[x=3\] |
\[\therefore \]Required number \[=10\times 3+6=30+6=36\] |
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