First you have all ten books, but then every time after, you loose one because you can't put the same book in the group twice.
10 * 9 * 8 * 7 = 5040 groups
Answer:
the range is 5-8 hours
Step-by-step explanation:
325+175t=1200
175t=875
875/175
t=5
325+175t=1725
175t=1400
1400/175
t=8
3 ways (uncertain)
1 red or blue or green + 3 other colours
The correct answer is three.
