Question:

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

Updated On: Apr 4, 2024
  • 243
  • 234
  • 217
  • 225
Hide Solution
collegedunia
Verified By Collegedunia

The Correct Option is D

Solution and Explanation

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 $=81+144=225$
Was this answer helpful?
0
0

Concepts Used:

Permutations

A permutation is an arrangement of multiple objects in a particular order taken a few or all at a time. The formula for permutation is as follows:

\(^nP_r = \frac{n!}{(n-r)!}\)

 nPr = permutation

 n = total number of objects

 r = number of objects selected

Types of Permutation

  • Permutation of n different things where repeating is not allowed
  • Permutation of n different things where repeating is allowed
  • Permutation of similar kinds or duplicate objects