Answer:
A .25
Step-by-step explanation:
Answer:
We know that the sum of the degrees of the vertices of the graph is twice the number of edges of the graph.
Let
be a graph with vertices 
Then
where
is the number of edges of the graph. Since the graph is regular of degree r then all vertices have degree r. Thus,

If order matters, then there are 12 ways to do this
If order does not matter, then there are 6 ways to do this
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We have 4 choices for the first slot and 3 choices for the next (we can't reuse a letter) so that's where 4*3 = 12 comes from
If order doesn't matter, then something like AB is the same as BA. So we are doubly counting each possible combo. To fix this, we divide by 2: 12/2 = 6
To be more formal, you can use nPr and nCr to get 12 and 6 respectively (use n = 4 and r = 2)
Answer & Step-by-step explanation:
So if 14% are over 65, and 320 residents are over 65, then we can say that 14% of the town is 320. Then, we can divide by 14 to find 1%, which is 22.857142857 Now we can multiply this by 100 to get 2285.7142857, which is the answer. To double check, you'd just find 14% of 2285.7142857 (multiply by 0.14) which is equal to 320. Because you can't have fractions of people, however, you'd have to round the answer up to 2286 people.
If that is too difficult to understand them hope this is easier
14% of the towns population is 320. Let P denote the towns population.
14/100 * P =320
14P/100 = 320
14P = 32000
divide both sides by 14
P = 2285.71
the towns population is 2286
Hope this helps!