Answer:
=(k−1)*P(X>k−1) or (k−1)365k(365k−1)(k−1)!
Step-by-step explanation:
First of all, we need to find PMF
Let X = k represent the case in which there is no birthday match within (k-1) people
However, there is a birthday match when kth person arrives
Hence, there is 365^k possibilities in birthday arrangements
Supposing (k-1) dates are placed on specific days in a year
Pick one of k-1 of them & make it the date of the kth person that arrives, then:
The CDF is P(X≤k)=(1−(365k)k)/!365k, so the can obtain the PMF by
P(X=k) =P (X≤k) − P(X≤k−1)=(1−(365k)k!/365^k)−(1−(365k−1)(k−1)!/365^(k−1))=
(k−1)/365^k * (365k−1) * (k−1)!
=(k−1)*(1−P(X≤k−1))
=(k−1)*P(X>k−1)
The <em><u>correct answer</u></em> is:
Ken will have run 3 laps and Hamid will have run 4.
Explanation:
To find this, we first find the number of seconds that will have passed when they meet again. We use the LCM, or least common multiple, for this. First we find the prime factorization of each number:
80 = 10(8)
10 = 5(2)
8 = 2(4)
4 = 2(2)
80 = 2(2)(2)(5)(2)
60 = 10(6)
10 = 5(2)
6 = 2(3)
60 = 2(2)(3)(5)
For the LCM, we multiply the common factors by the uncommon. Between the two numbers, the common factors are 2, 2 and 5. This makes the uncommon 2, 2, and 3, and makes our LCM
2(2)(5)(2)(2)(3) = 240
This means every 240 seconds they will both be at the start line.
Since Ken completes a lap in 80 seconds, he completes 240/80 = 3 laps in 240 seconds.
Since Hamid completes a lap in 60 seconds, he completes 240/60 = 4 laps in 240 seconds.
The answer is D. 140 cm². I think the circumference of the balloon means the circumference of the biggest circle. So the 21=2πr². While the surface area of a sphere is S=4πr². So the S≈140 cm².
