Problem Solving (PS) | A password to a certain database consists of digits that can

Total distint digits in one password: Minimum 8 & Maximum 10.

For 8 digits password, no. of distinct combinations possible= 8!*10C8= 10!/2!= 10!/2

For 9 digits password, no. of distinct combinations possible= 9!*10C9= 10!/1!= 10!

For 10 digits password, no. of distinct combinations possible= 10!*10C10= 10!/0!= 10!

Total possible passwords=
10!*0.5 + 10! + 10!= 10!*2.5

Time required to try one password= 12sec= 1/5 min.

Therefore, Time required to try 10!*2.5 password= 10!*2.5/5 min= 10!/2
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