Aptitude - Permutation and Combination - Discussion
Discussion Forum : Permutation and Combination - General Questions (Q.No. 7)
7.
How many 3-digit numbers can be formed from the digits 2, 3, 5, 6, 7 and 9, which are divisible by 5 and none of the digits is repeated?
Answer: Option
Explanation:
Since each desired number is divisible by 5, so we must have 5 at the unit place. So, there is 1 way of doing it.
The tens place can now be filled by any of the remaining 5 digits (2, 3, 6, 7, 9). So, there are 5 ways of filling the tens place.
The hundreds place can now be filled by any of the remaining 4 digits. So, there are 4 ways of filling it.
Required number of numbers = (1 x 5 x 4) = 20.
Discussion:
88 comments Page 7 of 9.
Karthick said:
9 years ago
How many 4 digit no can be formed with digits 1, 2, 3,4,5 which are divisible by 4 and digits not repeated?
a)144 b) 168 c) 182 d) none
Please tell me the correct answer.
a)144 b) 168 c) 182 d) none
Please tell me the correct answer.
Manisha said:
9 years ago
Nice answer@Justin.
Monisha said:
9 years ago
@Karthick.
Since last two digits must be 12 or 24 or 32 or 52,
The other two digits must be filled with either of the 3 numbers,
Thus,
(3*2)+(3*2)+(3*2)+(3*2) = 24 ways.
And hence the answer is none.
Since last two digits must be 12 or 24 or 32 or 52,
The other two digits must be filled with either of the 3 numbers,
Thus,
(3*2)+(3*2)+(3*2)+(3*2) = 24 ways.
And hence the answer is none.
Joe said:
9 years ago
Why isn't it just 5C2, from the 5 numbers that arent 5 to go in tens and hundreds, and picking two?
Vignesh said:
8 years ago
Please explain me, what would happen if another digit (0) is added to the series, i.e., 2,3,6,7,9,5 and 0 and the digits are to arranged without repetition such that the 3 digit number is divisible by 5?
Ambika said:
8 years ago
Write all the possible number using the digit 7, 0, 6 repetition of digits is not allowed.
Xiya said:
8 years ago
Can anyone say is 20 the right answer?
Because the question asked is number divisible by 5 and also not repeated?
Because the question asked is number divisible by 5 and also not repeated?
(1)
Dema said:
8 years ago
How 5p2? Please explain.
Pranav Khurud said:
8 years ago
If question is like, How many 3-digit numbers can be formed from the digits 2, 3, 5, 6, 7, 0, and 9, which are divisible by 5 and none of the digits is repeated?, In this situation unit place may be 0 or 5.
Shantanu said:
8 years ago
How many five digit numbers can be formed by using digits 0, 1, 2, 3, 4 and 5 without repetition. And number should be divisible by 6.
Can anyone solve this?
Can anyone solve this?
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