On the 1st place he can put 6 textbooks, on the 2nd 5 textbooks etc...
6 · 5 · 4 · 3 = 360
Answer: D) He can arrange textbooks in 360 ways.
I think it's consistent and independent because consistent means it has at least one solution (which it does) and independent means that it has exactly one solution. (i wasnt familiar with these terms so i googled what they meant, i apologise in advance if i am wrong)
The answer is 45 degrees. Hope this helps!
