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aev [14]
3 years ago
11

An instructor gives a class a set of 10 problems and says that the nal exam will consist of a random selection of 5 of the probl

ems. If a student has gured out how to solve 7 of the problems, what is the probability that he or she will answer at least 4 problems correctly?
Mathematics
1 answer:
sweet-ann [11.9K]3 years ago
8 0

Answer:

probability that he or she will answer at least 4 problems correctly = 0.5

Step-by-step explanation:

probability that he or she will answer at least 4 problems correctly is given as;

P (at least 4 correctly) = P (exactly 4 correctly) + P (all 5 correctly)

Since there are 10 problems. 4 is from the 7 problems chosen and 1 is from the 3 problems we can't figure out. Thus, P(exactly 4 correctly) = 7C4 x 3C1

Thus, P (at least 4 correctly) = [ (7C4) x (3C1) ] / (10C5)] + [(7C5)/(10C5)]

= [(35 x3)/252 ] + [21/252]

= [ 105/252 ] + [ 21/252 ]

= 126 / 252

= 0.5

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Sofia tem 52 triângulos retângulos isósceles iguais. Ela quer fazer quadrados usando alguns desses triângulos. Ela pode fazer qu
oee [108]

Answer:

Portanto, o Sofia pode fazer 6 tamanhos diferentes

Step-by-step explanation:

A fim de sermos capazes de determinar efetivamente quantos quadrados de diferentes tamanhos podem ser formados a partir do triângulo isósceles 52, resolvemos isso usando a fórmula

2 (n + 1) Onde n = 0 e todos os inteiros positivos

em outro para obter um tamanho diferente para os quadrados, temos que adicionar mais triângulos para aumentar o tamanho

a) quando n = 0

2 (0 + 1) = 2 × 1 = 2 triângulos isósceles iguais

A união de 2 triângulos isósceles forma um quadrado. Este é o primeiro quadrado

= 1 quadrado

b) quando n = 1

2 (1 + 1) = 2 × 2 = 4 triângulos isósceles iguais = 1 quadrado

c) quando n = 2

2 (2 + 1) = 2 × 3 = 6 triângulos isósceles iguais = 1 quadrado

d) quando n = 3

2 (3 + 1) = 2 × 4 = 8 triângulos isósceles iguais = 1 quadrado

e) quando n = 4

2 (4 + 1) = 2 × 5 = 10 triângulos isósceles iguais = 1 quadrado

f) quando n = 5

2 (5 + 1) = 2 × 6 = 12 triângulos isósceles iguais = 1 quadrado

Adicionamos o número total de triângulos usados

2 + 4 + 6 + 8 + 10 + 12 = 42 triângulos

42 triângulos de 52 triângulos formariam 6 quadrados com tamanhos diferentes

Vamos fazer mais um, onde n = 6

g) quando n = 6

2 (6 + 1) = 2 × 7 = 14 triângulos isósceles iguais = 1 quadrado

2 + 4 + 6 + 8 + 10 + 12 + 14 = 56 triângulos

Isso já excedeu o número dado de triângulos em questão.

Portanto, o Sofia pode fazer 6 tamanhos diferentes de quadrados usando 42 triângulos isósceles iguais

8 0
3 years ago
Given the trinomial, what is the value of the coefficient 'B' in the factored form?. . 2x^2 + 14xy - 36y^2 = 2(x + By)(x - 2y).
soldi70 [24.7K]
The value of the coefficient B is 9.

2(x+By)(x-2y)
=2(x^2 -2xy +Bxy -2By^2)
=2x^2 -4xy + 2Bxy - 4By^2

The original form is 2x^2 + 14xy - 36y^2

-36y^2 = -4By^2
B= 9
-4xy +2Bxy= 14xy
xy(-4 +2B)= 14xy
-4 + 2B = 14
2B = 18
B=9
3 0
3 years ago
Read 2 more answers
I’m giving 20 points and will give brainliest.
aleksley [76]

Answer:

Express 5 72 in simplest radical form:

Factorize the 72 in your expression:  

5√72 = 5√(2*2*2*3*3)

take a pair of two's and a pair of three's out of the radical sign:

5√72 = 5*2*3√2 = 30√2

this is the simplest radical form

Step-by-step explanation:

3 0
3 years ago
Read 2 more answers
What is the surface area of the square pyramid below?<br> 10 cm<br> 6 cm<br> 6 cm
Katyanochek1 [597]

Answer:

any picture or can you tell us what the amounts stand for?

4 0
3 years ago
What is 3.2 × 10−4 m/h in centimeters per second? A. 8.889 × 10−6 cm/s B. 8.889 × 10−5 cm/s C. 1.152 × 10−5 cm/s D. 1.152 × 10−7
atroni [7]
3.2 x 10^{-4} x  \frac{100}{3600} = 8.888 x  10^{-6}

therefore ur answer is OPTION A 8.889 x 10-6 cm/s
4 0
2 years ago
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