Yes you do.
The shelf is 24 in. long, so to fit, the total width of all the cases must be < 24 in.
If each case is 3/8 inches:
60 * 3/8 = 22.5
22.5 < 24, therefore they will all fit.
In a sequence of events, the
total possible number of ways all events can performed is the product of the
possible number of ways each individual event can be performed. Since there
are 10 openings
<span>P = 40 x 39 x 38 x 37 x 36 x 35
x 34 x 33 x 32 x 31 = 3.07599 x 10^15 different combinations</span>