Answer:
There are 67626 ways of distributing the chairs.
Step-by-step explanation:
This is a combinatorial problem of balls and sticks. In order to represent a way of distributing n identical chairs to k classrooms we can align n balls and k-1 sticks. The first classroom will receive as many chairs as the amount of balls before the first stick. The second one will receive as many chairs as the amount of balls between the first and the second stick, the third classroom will receive the amount between the second and third stick and so on (if 2 sticks are one next to the other, then the respective classroom receives 0 chairs).
The total amount of ways to distribute n chairs to k classrooms as a result, is the total amount of ways to put k-1 sticks and n balls in a line. This can be represented by picking k-1 places for the sticks from n+k-1 places available; thus the cardinality will be the combinatorial number of n+k-1 with k-1,
.
For the 2 largest classrooms we distribute n = 50 chairs. Here k = 2, thus the total amount of ways to distribute them is
.
For the 3 remaining classrooms (k=3) we need to distribute the remaining 50 chairs, here we have
ways of making the distribution.
As a result, the total amount of possibilities for the chairs to be distributed is 51*1326 = 67626.
Answer:
a) P ( 3 ≤X≤ 5 ) = 0.02619
b) E(X) = 1
Step-by-step explanation:
Given:
- The CDF of a random variable X = { 0 , 1 , 2 , 3 , .... } is given as:
Find:
a.Calculate the probability that 3 ≤X≤ 5
b) Find the expected value of X, E(X), using the fact that. (Hint: You will have to evaluate an infinite sum, but that will be easy to do if you notice that
Solution:
- The CDF gives the probability of (X < x) for any value of x. So to compute the P ( 3 ≤X≤ 5 ) we will set the limits.

- The Expected Value can be determined by sum to infinity of CDF:
E(X) = Σ ( 1 - F(X) )

E(X) = Limit n->∞ [1 - 1 / ( n + 2 ) ]
E(X) = 1
Arranging them in ascending order :
21 , 21 , 30 , 44, 49, 52
Median = (30 + 44) ÷ 2
Median = 37 mins
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Answer: Median = 37 mins (Answer D)
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Answer:
81π
Step-by-step explanation:
-The sum of central angles in a circle add up to 360°.
-Let x be the area of the circle.
-Given the area of a 120° is 27π, the circles area can be calculated as:

Hence, the area of the circle is 81π