a locker opened by combination of 4 keys.a man have four key and he know that 3rd no. key will be placed at first key hole but don't know about rest.so tell me maximum no. of attempt he will make to open locker.  Pick:
A) 6 B) 8 C) 10 D) 5 E) 4
as no. 3rd key position get fixed.so we have to calculate total no. of configuration of rest three key.   which is permutation of three item,3P3=3!=6   answer 6
<result>A</result>
a locker opened by combination of 4 keys.a man have four key and he know that 3rd no. key will be placed at first key hole but don't know about rest.so tell me maximum no. of attempt he will make to open locker.