You can arrange 4 in 2 ways 1x4 and 2x2.
24, 1*2*3*4
In a line in 6! = 6*5*4*3*2*1 = 720 ways.
24.
24 ways
4! 4 * 3 * 2 = 24 ways ==========
8
4
24
5
Since there are 4 letters, they can be arranged 4! ways (4*3*2*1) or 24 ways.
The answer is 5 factorial or 5*4*3*2*1 or 120