We must find UNIQUE combinations because choosing a,b,c,d... is the same as d,c,b,a...etc. For this type of problem you use the "n choose k" formula...
n!/(k!(n-k)!), n=total number of choices available, k=number of choices made..
In this case:
20!/(10!(20-10)!)
20!/(10!*10!)
184756
Answer:12/87
Step-by-step explanation: You first have to add up all of the birds present. Then you have to see how many of the type you are looking for is there. The number of the type of bird goes on top of the number of total birds.
Answer:
21
Step-by-step explanation:
21-12=9
Answer:
Step-by-step explanation:
45 gallons but your questtion doesnt make sense because you dont give us the number in gallons per minute
