Answer:
B
Step-by-step explanation:
got it right on EGDE 2020
<span>X-Y=4,
X+Y=2
-------------add
2x = 6
x = 3
X - Y =4
3 - Y = 4
Y = 3 - 4
Y = -1
solution (3 , -1)</span>
Using the binomial distribution, it is found that:
The probability that the student will get 15 correct questions in this test by guessing is 0.0207 = 2.07%.
For each question, there are only two possible outcomes, either the guess is correct, or it is not. The guess on a question is independent of any other question, hence, the binomial distribution is used to solve this question.
Binomial probability distribution
The parameters are:
- x is the number of successes.
- n is the number of trials.
- p is the probability of a success on a single trial.
In this problem:
- There are 20 questions, hence
.
- Each question has 2 options, one of which is correct, hence

The probability is:

In which:







Then:

The probability that the student will get 15 correct questions in this test by guessing is 0.0207 = 2.07%.
You can learn more about the binomial distribution at brainly.com/question/24863377
Answer:
$870 in his bank account
Step-by-step explanation:
420 / 3 = 140
140 * 6 = 840
840 + 30 = 870
Answer:
x = 2 2/3
Step-by-step explanation:
(1/3)/(1/8) = 2 2/3