Question

how many 7-digit number can be formed by using the digit 1,2,0,2,4,2,4
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Answer 1

Answer:

360

Step-by-step explanation:

You’ve given four characters (0, 1, 2 and 4) to form 7-digit numbers.

The characters 0 and 1 each can be used once.

The character 2 can be used thrice and the character 4 twice.

To simplify your problem; first I generalize all numbers that can be formed likewise (including those starting with ‘0’).

Such numbers will be = (7!) / {(3!)*(2!)*(1!)*(1!)} = 420.

Now, we should eliminate those numbers starting with ‘0’ from above 420 possible numbers.

Such 7-digit numbers starting with ‘0’ are = (6!) / {(3!)*(2!)*(1!)} = 60.

Therefore, the answer to your question is (420 - 60) = 360.

hope it helpssss.....

Answer 2

48 is the correct answer