In this case, all letters are unique.
Start by holding the first letter:
E - XAM
E - XMA
E - MAX
E - MXA
E - AXM
E - AMX
So there are 6 combinations here.
Repeat for all 4 letters.
6 x 4 = 24
This is same as 4x3x2x1.
For 3 unique characters, it is 3x2x1.
For 5 unique characters, it is 5x4x3x2x1
And so on...
Answer:
1.FILTER WATER 2.FILTER CLOTH
3.LIQUIDS
4.INSOLUBLE
5.DIFFERENCE
8 divided by 12 is about .67
the degrres fell .67 in 1 hr
Answer: 90
Explanation: The pattern is add 3 then the next set is double. [9-6=3 then 18-9=9(or doubled)] and the pattern continues and because 45-42=3 the next number set would be 45 doubles which equals 90.