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2 years ago

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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?

1 answer:

sweet-ann [11.9K]2 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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2 years ago

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2 years ago

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Read 2 more answers

Paisley has 8\tfrac{1}{4}8 4 1 cups of yogurt to make smoothies. Each smoothie uses \tfrac{11}{16} 16 11 cup of yogurt. How

Ivenika [448]

Given:

Total Yogurt = $8\dfrac{1}{4}$ cups

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The number of smoothies that Paisley can make with the yogurt.

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We know that,

$\text{Number of smoothies}=\dfrac{\text{Total yogurt}}{\text{Yogurt required for each smoothie}}$

Substituting the given values, we get

$\text{Number of smoothies}=\dfrac{8\dfrac{1}{4}}{\dfrac{11}{16}}$

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Therefore, the number of smoothies is 12.

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