This is a problem dealing with permutations and combinations.
Order does not matter in this problem.
Since order doesn't matter, it is a combination.
Repetition matters, since you can't have the same person count as two people.
There are twelve slots.
_ _ _ _ _ _ _ _ _ _ _ _
Each slot needs to be multiplied by the next.
_*_*_*_*_*_*_*_*_*_*_*_
Now we have to fill in the slots.
Each slot will be filled with a number one less than the one before it. It has to be one less, since repetition matters.
The numbers will be decreasing from 30, since there are 30 possible people.
30 * 29 * 28 * 27 * 26 * 25 * 24 * 23 * 22 * 21 * 20 * 19
Multiply these numbers together and you get your answer.
41,430,393,164,160,000 ways
Well if I did my math correctly I do believe the perimeter should be 392 ft.
6÷2.5= 2.4
2.4×35=84
8÷2.5= 3.2
3.2×35=112
84×2
112×2
_____
392
you mult. by 2 because it's a room which usually has four walls and I imagined it being a rectangle.
Combine like terms and then divide out the coefficient to solve for n
To solve this, you first subtract 60 by 18 to get 42
You then divide this by 2 to get 21
So, it'll take 21 minutes
Answer:
draw the same shape but multiply all the sizes to be bigger or smaller
