ABC ∆ where Angle A =90° , AB = 12 m, AC = 9 m . Find BC ?

Choice test you know the answer to the third question is not b or c you sure about a,d,or e. If you guess, what is the probabili

MrRissso [65]

If there were just one question, then the probability of guessing correctly would be 1/3.

Since all the answers are independent (the answer to one question has no bearing on the answers to the others), then this is the case with each question, so the chances of guessing all answers correctly is 1/3 × 1/3 × 1/3 = 1/27. Independent choices are linked by multiplication.

To have exactly 2 answers correct, we have to think of which one is wrong: there are 3 questions and any single one could be wrong. The probability that the first question is wrong is 2/3. And we know that the probabilities of the other two being right is 1/3 each, so the probability of just the first question being wrong and the others right is 2/3 × 1/3 × 1/3 = 2/27. But this is just one of the three cases: 1/3 × 2/3 × 1/3 and 1/3 × 1/3 × 2/3 also both equal 2/27 each. So here we add the cases together: 2/27 + 2/27 + 2/27 = 6/27 = 2/9. So the answer to part (a) of your question is 2/9.

To solve (b) Consider that (b) is the same as (a) with "all answers right" added in. So you can simply add answer (a) to the chance of guessing all answers correctly.

To solve (c) it might help you to think of the equivalent problem: what is the probability of getting 0 correct plus the probability of getting 1 correct?

6 0

3 years ago

Six friends share 2 burritos equally.<br> Each person gets<br> of the burritos.

Makovka662 [10]

Answer:

1/3 of the burrito

Step-by-step explanation:

2 burritos. Cut each one in 3 pieces. And each friend gets one piece out of it.

7 0

3 years ago

Arandom sample of n1 =12 students majoring in accounting in a college of business has a mean grade-point average of 2.70 (where

antiseptic1488 [7]

Answer:

We accept the null hypothesis that the mean gpa's are equal, with the 5 percent level of significance.

Step-by-step explanation:

We have these following hypothesis:

Null

Equal means

So

$\mu_{1} = \mu_{2}$

Alternative

Different means

So

$\mu_{1} \neq \mu_{2}$

Our test statistic is:

$\frac{\overline{Y_{1}} - \overline{Y_{2}}}{\sqrt{\frac{s_{1}^{2}}{N_{1}} + \frac{s_{2}^{2}}{N_{2}}}}$

In which $\overline{Y_{1}}, \overline{Y_{2}}$ are the sample means, $N_{1}, N_{2}$ are the sample sizes and $s_{1}, s_{2}$ are the standard deviations of the sample.

In this problem, we have that:

$\overline{Y_{1}} = 2.7, s_{1} = 0.4, N_{1} = 12, \overline{Y_{2}} = 2.9, s_{2} = 0.3, N_{2} = 10$

So

$T = \frac{2.7 - 2.9}{\sqrt{\frac{0.4}^{2}{12} + \frac{0.3}^{2}{10}}} = -1.3383$

What to do with the null hypothesis?

We will reject the null hypothesis, that is, that the means are equal, with a significante level of $\alpha$ if

$|T| > t_{1-\frac{\alpha}{2},v}$

In which v is the number of degrees of freedom, given by

$v = \frac{(\frac{s_{1}^{2}}{N_{1}} + \frac{s_{2}^{2}}{N_{2}})^{2}}{\frac{\frac{s_{1}^{2}}{N_{1}}}{N_{1}-1} + \frac{\frac{s_{2}^{2}}{N_{2}}}{N_{2} - 1}}$

Applying the formula in this problem, we have that:

$v = 20$

So, applying t at the t-table at a level of 0.975, with 20 degrees of freedom, we find that

$t = 2.086$

We have that

$|T| = 1.3383$

Which is lesser than t.

So we accept the null hypothesis that the mean gpa's are equal, with the 5 percent level of significance.

7 0

3 years ago

Find the values of x and y. ....

alex41 [277]

If you substitute the values x = 0 and y = −5 into the second equation, you get a false statement: 2(−5) − 10 = 2(0). To solve this system, try rewriting the first equation as x = 2y − 8. Then substitute 2y − 8 in for x in the second equation, and solve for y. The correct answer is x = −2, y = 3.

5 0

3 years ago

23÷10=<br> how to work it out

zaharov [31]

The answer is 2.3 :)

7 0

4 years ago

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