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solmaris [256]
3 years ago
6

una caja contiene 2 bolitas blancas y 3 blancas .la probabilidad de que la primera extraída sea blanca y la segunda sea negra ,

sin reponer la primera
Mathematics
1 answer:
zzz [600]3 years ago
6 0

si cinco son blancas como va a ver una negra ?

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The College Board reports that 2% of students who take the SAT each year receive special accommodations because of documented di
Sonbull [250]

Answer:

(a) P(X=1) = 0.3079

(b) P(X≥1) = 0.3965

(c) P(X≥2) = 0.0886

(d) P(X≤1.9) = 0.9114

(e) Expected no. of hours = 3.594 hours

Step-by-step explanation:

We have,

p = 0.02

n = 25

q = 1-p

q = 0.98

We will use the binomial distribution formula to solve this question. The formula is:

P(X=x) = ⁿCₓ pˣ qⁿ⁻ˣ

where n = total no. of trials

           x = no. of successful trials

           p = probability of success

           q = probability of failure

Let X be the number of students who received a special accommodation.

(a) P(X=1) = ²⁵C₁ (0.02)¹ (0.98)²⁵⁻¹

          = 25*0.02*0.61578

P(X=1) = 0.3079

(b) P(X≥1) = 1 - P(X<1)

               = 1 - P(X=0)

               = 1 - (²⁵C₀ (0.02)⁰ (0.98)²⁵⁻⁰)

              = 1 - 0.6035

   P(X≥1) = 0.3965

(c)  P(X≥2) = 1 - P(X<2)

                 = 1 - [P(X=0) + P(X=1)]

                 = 1 - (0.6035 + 0.3079)

                 = 1 - 0.9114

     P(X≥2) = 0.0886

(d) The probability that the number among 25 who received a special accommodation is within 2 standard deviations of the expected number of accommodations. This means we need to compute the probability P(X-μ≤2σ). For this we need to calculate the mean and standard deviation of this distribution.

μ = np = (25)*(0.02) = 0.5

σ = \sqrt{npq} = √(25)*(0.02)*(0.98) = √0.49 = 0.7

P(X-μ≤2σ) = P(X - 0.5≤ 2(0.7)) = P(X≤ 1.4 + 0.5) = P(X≤1.9)

P(X≤1.9) = P(X=0) + P(X=1)

             = 0.6035 + 0.3079

P(X≤1.9) = 0.9114

(e) Student who does not receive a special accommodation i.e. X=0 is given 3 hours for the exam whereas an accommodated student P(X>0) is given 4.5 hours. The expected average number of hours given on the exam can be calculated as:

Expected no. of hours = ∑x*P(x)

                                     = 3*P(X=0) + 4.5*P(X>0)

                                     = 3*0.6035 + 4.5(1 - P(X≤0))

                                     = 1.8105 + 4.5(1 - 0.6035)

                                     = 1.8105 + 1.78425

Expected no. of hours = 3.594 hours

5 0
3 years ago
Read 2 more answers
The event coordinator asks you to determine how many students participated in the track-and-field day. The total number of stude
kakasveta [241]
584 is the total number of students in the school.

5/8 are in seventh grade and 3/8 are in eighth grade.

4/5 of the seventh graders participated in the track meet, so there were (4/5 · 5/8) · 584 students in the seventh grade participating in the track meet.

7/8 of the eighth graders participated, so there were (7/8 · 3/8) · 584 students in the eighth grade participating in the track meet.

So, all together, there were

(4/5 · 5/8) · 584 + (7/8 · 3/8) · 584 students from the school in the track meet.

Let's simplify as you asked:

(4/5 · 5/8) · 584 + (7/8 · 3/8) · 584 = [(4/5 · 5/8) + (7/8 · 3/8)] · 584 (distributive property - factoring)

= [20/40 + 21/64] · 584 (multiply fractions)

= (1/2 + 21/64) 584 (reduce the first fraction to lowest terms)

= (32/64 + 21/64) 584 (getting a common denominator)

= (53/64) 584 (combine/add the two fractions)

= 483.625 (multiply together)

All together, there were: 483.625 students in the meet.
8 0
3 years ago
Please help Help !!!!!!!
Vilka [71]
I think the correct answer to the question is 9
6 0
3 years ago
Read 2 more answers
Asavings account balance was $135.10 before a withdrawl of $60,a deposit of $22.50,and a withdrawl of $45.What was the after the
SSSSS [86.1K]

Answer:

$52.60

Step-by-step explanation:

Start with 135.10 and subtract the withdrawls (60, 45)

135.10-60-45 = 30.10

Add the deposit 22.50

30.10 + 22.50 = 52.60

3 0
3 years ago
What is the solution to the equation? 13 3/4+x=7 1/4
oksano4ka [1.4K]

Answer:

x=-13/2

Step-by-step explanation:

13 3/4=55/4

7 1/4=29/4

---------------------

55/4+x=29/4

x=29/4-55/4

x=-26/4

simplify

x=-13/2

4 0
3 years ago
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