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lina2011 [118]
2 years ago
9

On an island there are 7 cities each 2 of them connected by a direct road they are building a 8th city they also want it to conn

ect with the other 7 existing cities how many roads will there be after they build the 8th city
Mathematics
1 answer:
Katarina [22]2 years ago
8 0

Answer:

After the 8th city is built there will be 28 roads between the cities

Step-by-step explanation:

The given parameters are;

The number of cities initially on the island = 7 cities

The number of roads between each 2 cities = 1 road

Therefore, we have the number of roads between the 7 cities are;

7 cities taking 2 at a time = ₇C₂

_7C_2 = \dfrac{7!}{(7 - 2)!\cdot 2!} = 21

The initial number of roads between the 7 cities = 21 roads

The number of roads, 'n' there will be after the 8th city is built is therefore;

n = _8C_2 = \dfrac{8!}{(8 - 2)!\cdot 2!} = 28

The number of roads there will be after the 8th city is built, n = 28 roads.

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Does the graph represent a function?
Paladinen [302]

Answer:

Yes, the graph is a function.

Vertical line test proves so.

5 0
2 years ago
To rent a certain meeting room, a college charges a reservation fee of $15 and an additional fee of $6 per hour. The chemistry c
Dafna1 [17]

Answer:

To spend at most $93, they need to rent the room less than or equal 13 hours.

Step-by-step explanation:

<u><em>The complete question is</em></u>

To rent a certain meeting room, a college charges a reservation fee of $15 and an additional fee of $6 per hour. The chemistry club wants to spend at most $93 on renting a room. What are the possible numbers of hours the chemistry club could rent the meeting room? Use t for the number of hours. Write your answer as an inequality solved for t,

Let

t ----> the number of hours

we know that

I this problem the word "at most" means "less than or equal to"

The number of hours rented multiplied by the cost per hour, plus the reservation fee, must be less than or equal to $93

so

The inequality that represent this situation is

6t+15\leq 93

solve for t

subtract 15 both sides

6t\leq 93-15

6t\leq 78

Divide by 6 both sides

t\leq 13\ hours

therefore

To spend at most $93, they need to rent the room less than or equal 13 hours.

6 0
3 years ago
What is the product of i^2(2i^2-5)
Black_prince [1.1K]
Sorry this just got deleted :( ill post it again

i^2(2i^2 - 5)

= 7 

I'm sorry I'm bad at explaining how i solved it
4 0
3 years ago
1.98 subtracted by 0.99
Oksana_A [137]

Answer:

0.99

Step-by-step explanation:

1.98 - 0.99 is 0.99.

Easy.

Just do it like you would any other problem.

5 0
3 years ago
Read 2 more answers
Please help, I'm giving Brainliest to the right answer!!
Neko [114]
The correct answer is  D

7 0
3 years ago
Read 2 more answers
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