How many three digit odd numbers can be formed by using the digits 1,2,3,4,5,6
If: 1) the repetition of digits is not allowed?
2) the repetition of digits is allowed?
Asked by Topperlearning User | 4th Jun, 2014, 01:23: PM
Expert Answer:
For a odd number, we must have 1,3 or 5 at the unit's place. So there are 3 ways of filling the unit's place.
1) Since the repetition of digits is not allowed, the ten's place can be filled with any of the remaining 5 digits in 5 ways. Now, four digits are left. So hundred's place can be filled in 4 ways.
So the required numbers = 3 x 5 x 4 = 60
2) Since the repetition of digits is allowed, so each of the ten's and hundred's place can be filled in 6 ways.
Hence, required numbers = 3 x 6 x 6 = 108
Answered by | 4th Jun, 2014, 03:23: PM
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