Suppose a quiz contains 20 true/false questions. You know the correct answer to the first 10 questions. You have no idea of the correct answer to questions 11 through 20 and decide to answer each using the coin toss method. Calculate the probability of obtaining a total quiz score of at least 85%

0.1719

Step-by-step explanation:

Given that:

A quiz contains 20 questions and 10 questions have been answered rightly

We are to determine the probability of getting a total quiz score of 85%

i.e 0.85 (20) = 17

Let's not forget that 10 is correctly answered out of 17. that implies that we only have 7 more questions to make a decision on.

where;

n = 10,

p + q = 1, 0.5 + q = 1

q = 1 - 0.5

q = 0.5

Let X be the random variable that follows the binomial distribution. Then ;

where x = 7

P(X ≥ 7) = 0.1719

english, cause i can’t you

let's cover over the formula of the vertex:

y = a(x – h)^2 + k

in this formula, (h,k) are the vertex, always remember that the positive or negative value of the vertex is based on the sign it has.

for example, if the vertex is -3,-6 then both the x and y value would have the positive sign attached to it and if it were a positive x and y value, then a negative sign would be attached to it.

with that being said, for our problem the x value is a positive one so we are looking for a number with a negative sign next to it, in this case the first and second choice.

however, for the first answer choice it isn't quite part of the formula so we know that the answer choice correctly displays the x value.

to confirm, we can see if the -1 fits correctly with the second answer choice, and as mentioned above a negative number will have a positive sign attached to it. so, for our problem we can see that -1 has been changed to +1, so we can confirm that the second answer choice is correct.

hence, our final answer is y=(x - 1)^2 + 1