A series of math books has 7 volumes. In how many ways can they be arranged on a shelf so that they are not in order?

Question

anonymous · Answer

Answer I got was 7!-1 but can it be 7! -2?

amistre64 · Answer

what does 'in order' signify?  does it mean no 2 volumes are next to each other?

amistre64 · Answer

if there is only one way for them to be in order .... assuming left to right

then 7!-1 is correct

anonymous · Answer

they have to be in order, so like 1,2,3... but i was also thinking can it not start from 7,6,5...

amistre64 · Answer

if 'in order' is not defined for you, then you should define it beforehand and work the solution according to your definition

anonymous · Answer

okay thanks. i'll define it.

amistre64 · Answer

:)  good luck