Question
How many different nine digit numbers can be formed
from the number 66 55 99 222 by rearranging its digits so that the odd digits occupy even positions only?Solution
Number of even places = 4 Number of even digits = 5 (6,6,2,2,2) Number of odd places = 5 Number of odd digits = 4 (5,5,9,9) Since 5 & 9 are repeated two times odd digits can be arranged in 4!/(2!×2! ) = 6 ways Since 6 is repeated two times & 2 is repeated three times even digits can be arranged in 5!/(2! ×3!) = 10 ways Hence, the required number of ways = 6 × 10 = 60 ways.
More Permutation and combination Questions
82, 65, 59, 64, 80, 113
164, 304, 433, 551, 658, 752
12, 18, 14, 17, 16, 15, 18, 15
16, 16, 32, 128, 1024, 16384
- Find the wrong number in the given number series.
43, 56, 80, 121, 173, 238 182, 240, 306, 380, 462, 558
- Find the wrong number in the given number series.
8, 12, 21, 46, 95, 195 34, 51, 85, 119, 185, 221
Find the wrong number in the given number series.
3, 8, 15, 24, 35, 50, 63
Find the wrong number in the given number series.
12, 6, 6, 9, 18, 54
Relevant for Exams:
