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Aug 20, 2023
 #1
avatar+4 
-1

To solve this problem, let's break it down into steps:

Step 1: Consider the scientists as one group, since they need to sit together. We can think of them as a single entity. So, now we have 6 entities: the group of scientists, the two mathematicians, the journalist, and the remaining three seats around the table.

 

Step 2: Since the mathematicians must sit next to each other, we can think of them as a single entity as well. Now we have 5 entities: the group of scientists, the mathematicians, the journalist, and the remaining three seats.

 

Step 3: Let's arrange the 5 entities around the table. We can think of this as arranging the entities in a line, and then considering the starting point. There are 5! (5 factorial) ways to arrange the entities in a line.

 

Step 4: However, since the table is circular and rotating the seating arrangement doesn't create a new arrangement, we need to divide by 5 to account for the rotations. This is because if we fix one entity (say, the group of scientists) in a specific position, we can rotate the other entities around the table without changing the overall arrangement.

 

Step 5: Finally, the mathematicians can be arranged amongst themselves in 2! (2 factorial) ways. Step 6: Putting it all together, the total number of different arrangements is (5! / 5) * 2! = 4! * 2! = 24 * 2 = 48.

 

Therefore, there are 48 different arrangements possible if the scientists must all sit together and the mathematicians must sit next to each other.

 

- Jade!

Aug 20, 2023
 #1
avatar+189 
0

It is best for these problems to use a picture, and the picture should make it clearer how to proceed. With the given information, I was able to create the following diagram below:

 

Note that G is the center of the circle. Our goal is to find the length of \(\widehat{DE}\), which is essentially asking for the arc length. The typical arc length formula for degrees is \(S = 2 \pi r * \frac{\theta}{360^{\circ}}\) where S is the arc length, r is the radius of the circle, and \(\theta\) is the angle of the central angle of the arc, which is \(\angle DGE\) in this case.

 

We can modify this formula somewhat because we already know the circumference. Since the given information states that \(C = 2 \pi r = 24\), we can substitute that into the arc length formula, which turns it into \(S = 24 * \frac{\theta}{360^{\circ}}\).

 

Now, we must find the central angle, which we can use the Inscribed Angle Theorem to find the measure of the central angle. The Inscribed Angle Theorem states that the measure of the central angle is twice that of the corresponding inscribed angle. Applying that theorem to this particular case, \(2m \angle DFE = m \angle DGE\).

 

\(2 m \angle DFE = m\angle DGE \\ 2 * 60^\circ = m \angle DGE \\ m \angle DGE = 120^\circ\)

 

Now that we know the measure of the central angle, we can find the arc length finally.

 

\(S = 24 * \frac{\theta}{360^{\circ}} \\ S = 24 * \frac{120^{\circ}}{360^{\circ}} \\ S = 24 * \frac{1}{3} \\ S = 8 \text{ units}\)

 

The question asks to represent the answer as a common fraction, so I suppose \(S = \frac{8}{1} \text{ units}\) would be the right answer in this case.

Aug 20, 2023

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