Consider a set S = {1000, 1001, 1002, ........ 9999}. The numbers in set ‘S’ have atleast one digit as 2 and atleast one digit as 5 are ________.
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I have done like
One 2 and one 5 can arrange like 2. _. _ 5 =$8\times 8\times \left ( 4!+\frac{4!}{2!} \right )$
Two 2 and one 5 (similarly two 5 and one 2)=$8\times \left ( \frac{4!}{2!} \right )\times 2$
Three 2 and one 5 (similarly three 5 and one 2)=$\left ( \frac{4!}{3!} \right )\times 2$
but ans not matching
Where have I done mistake?
