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:
C
Step-by-step explanation:
Rewrite as (2^1/2 + 2^1/2)*(18^1/2-2^1/2) = 8
7/10x - 5 = 1/2x
7/10x - 1/2x = 5
7/10x - 5/10x = 5
2/10x = 5
x = 5 / (2/10)
x = 5 * 10/2
x = 50/2
x = 25 gallons <===
Answer: A 729
Step-by-step explanation: