12. How many 7 digit numbers can be formed using the digits 1, 2,0, 2, 4,2 and 4. with the help of (permutations with reputations)
please give answer it's urgent
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12. How many 7 digit numbers can be formed using the digits 1, 2,0, 2, 4,2 and 4. with the help of (permutations with reputations)
please give answer it's urgent
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Answer:
43Q:
How many 7 digit numbers can be formed using the digits 1, 2, 0, 2, 4, 2, 4?
A) 120
B) 360
C) 240
D) 424
Answer: B) 360
Explanation:
There are 7 digits 1, 2, 0, 2, 4, 2, 4 in which 2 occurs 3 times, 4 occurs 2 times.
Number of 7 digit numbers = 7!3!×2! = 420
But out of these 420 numbers, there are some numbers which begin with '0' and they are not 7-digit numbers. The number of such numbers beginning with '0'.
=6!3!×2! = 60
Hence the required number of 7 digits numbers = 420 - 60 = 360