Answer:
a) h(x; 7, 5, 12) = (⁵Cₓ)( ⁷C₇₋ₓ) / (¹²C₇)
b) 2.92
Step-by-step explanation:
a)
Here
Number of interviewees = N = 12
Number of job openings = M = 5
Interviews schedules for the first day = n = 7
N − M = 12 - 5 = 7
Using hypergeometric distribution:
Let X be the no. top four candidates interviewed on first day.
The probability mass function of X:
P(X = x) =
/ 
It can be written as:
h(x; n, M, N) =
/
= (5Cx) (7C7-x) / (12C7)
= (⁵Cₓ)( ⁷C₇₋ₓ) / (¹²C₇)
h(x; 7, 5, 12) = (⁵Cₓ)( ⁷C₇₋ₓ) / (¹²C₇)
b)
The expectation is: E(X) = np
E(X) = n * M/N
= 7 * 5/12
= 7 * 0.41667
= 2.9167
If the rectangle has a fixed width of 300, it means that

where
and
are width and length, respetively.
So given the length
, the are would be

B ( i think )
i might be wrong though
Step-by-step explanation:
For the 1st picture,
The 2nd option is the answer.
Let say we have

Replace it into the recursive formula.

We are given a,1 and a,2 so the 3rd terms has to be

So the second option is the answer.
For the second picture, a geometric sequence is a group of terms that has the same ratio between each consecutively.
Infinite means going on forever
The fourth option is the answer.
The probability that two of the coins will be tails is 1/2
It is 1/2 because "at least two tails" means that two tails and the rest of the number of tails, which is 3. In total the three coins have 6 sides. The chance of having two tails and one is three out of 6, simplified is 1/2 ;)