Mathematics, 22.06.2019 18:10 Harambe659

An instructor gives her class a set of 10 problems with the information that the final exam will consist of a random selection of 5 of them. if a student has figured out how to do 7 of the 10 problems, what is the probability that he will answer correctly (a) all 5 problems? (b) at least 4 of the problems?

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Answer from: angelrgomez01

Answer with explanation:

It is given that An instructor gives her class a set of 10 problems.

The final exam will consist of a random selection of 5 of them.

A student has figured out how to do 7 of the 10 problems.

We know that the probability of an event is defined as the ratio of number of favorable outcomes to the total number of outcomes.

The probability that he will answer all the 5 problems correctly is:

given by:

$\dfrac{7_C_5}{{10}_C_5}$

Since he may chose 5 questions out of 7 questions that a student knows how to do and total outcomes is the selection of 5 questions from the total 10 questions.

Hence, on solving we get:

$=\dfrac{\dfrac{7!}{5!\times (7-5)!}}{\dfrac{10!}{5!\times (10-5)!}}\\\\\\\\=\dfrac{\dfrac{7!}{5!\times 2!}}{\dfrac{10!}{5!\times 5!}}$

On further solving we get:

Probability=0.083

The probability that he will answer at least four correctly is given by:

$\dfrac{7_C_4\times 3_C_1+7_C_5}{10_C_5}$

( Since, he may answer correctly four or five questions)

( If he answer four answers correctly, this means he choose 4 questions from 7 questions and 1 from the remaining.

and if he answers five answer correctly then he choose it from the 7 questions a student know)

Hence, on solving we get:

$Probability=\dfrac{2}{9}\\\\\\Probability=0.222$

Hence, we get Probability= 0.222

Answer from: Quest

i'm not sure what you mean but in todays world there is a lot of women that are the bread winners in the family. there is a lot more single mothers now that are going back to get an education which is boosting the economy. i believe there has been a boost in the economy due to women the cosmetic industry is boosting, chemist, the sky is becoming the limit for women in todays economy. most women are also putting off having kids just to make sure they have a education. i don't know how these two relate though to scriptures because it's not the way the lord wanted it. the man is suppose to be the bread winner and due to social media and the easy access we have there is a lot of cheating going on.

step-by-step explanation:

Answer from: Quest

answer: answer

step-by-step explanation:

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