Since the order of the books chosen doesn't matter, we use the combination formula to find the number of possible selections. Recall that a combination of k items from a set of n items is given by

.
In this problem, n = 8 and k = 3. So the number of possible selections is

. Thus the answer is 56.
Answer:cost of each donut =$4
and cost of each cup of hot chocolate =$2
Step-by-step explanation:
Step 1
Let donuts be represented as d
and cups of hot chocolate be rep as c so that
5 donuts and 2 cups of hot Chocolate costing 24$ will be expressed as
5 d+ 2 c= 24
And 2 donuts and 3 cups of hot chocolate costing 14$ will be expressed as
2d +3 c= 14
Step 2
Using elimination method,Multiply equation 1 by 3 and equation 2 by 2
15d+ 6c= 72----equation 3
4d+ 6c= 28-----equation 4
Subtracting equation 4 from equation 3 gives us
11 d=44
d= 44/11
d= 4
To find c, using equation 1
5 d+ 2 c= 24
5 x 4+ 2c=24
20+2c=24
2c=24-20
2c=4
c=4/2 =2
cost of each donut =$4
and cost of each cup of hot chocolate =$2
The percentage that the number of airlines with an average airplane age of 14 is less than the number of airlines with an average airplane age of 11 is:
B. 20%.
<h3>What is a percentage?</h3>
The percentage of an amount a over a total amount b is given by a multiplied by 100% and divided by b, that is:

The percentage of airlines with an average age of 14 years is:

The percentage of airlines with an average age of 11 years is:

The difference is:
33.33% - 13.33% = 20%.
Hence option B is correct.
More can be learned about percentages at brainly.com/question/10491646
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Answer: B is true
Step-by-step explanation:
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C is 20 degrees. Pls mark brainliest