Question

The number of three digit numbers in which $9$ appears only in one place is

• A. 243
• B. 234
• C. 217
• D. 225

Answer 1

Answer: (D)

The number of three digit numbers in which 9 appears at hundred place only is $=1\times 9\times 9=81$ Similarly, the number of three digit numbers in which 9 appears at ten or unit place only is
$=(8\times 1\times 9)\times 2=144$
So, required number $=81+144=225$