1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
Elodia [21]
3 years ago
13

A student takes an exam containing 18 true or false questions. If the student guesses, what is the probability that he will get

exactly 6 questions right? Round your answer to four decimal places.

Mathematics
1 answer:
V125BC [204]3 years ago
3 0
Use this formula.
and solution is:[(18!)/(6!×(18-6)!)]×(1/2)^6×(1-1/2)^(18-6)≈0.0781604
7.8%

You might be interested in
If there are 15 pistachios for every 5 bowls, how many pistachios are in 4 bowls
Pani-rosa [81]

Answer:

12 pistachios

Step-by-step explanation:

We need to find the unit rate. So we divide 5 from 15.

15/5=3

So we know that 1 bowl has 3 pistachios(which I think needs more).

Now we need to find how many pistachios are in 4 bowls. Which means we multiply 4 and 3.

4x3=12

So there are 12 pistachios in 4 bowls.

---

hope it helps

7 0
2 years ago
Read 2 more answers
Find the exact value of the expression.<br> tan( sin−1 (2/3)− cos−1(1/7))
Sonja [21]

Answer:

\tan(a-b)=\frac{2\sqrt{5}-20\sqrt{3}}{5+8\sqrt{15}}

Step-by-step explanation:

I'm going to use the following identity to help with the difference inside the tangent function there:

\tan(a-b)=\frac{\tan(a)-\tan(b)}{1+\tan(a)\tan(b)}

Let a=\sin^{-1}(\frac{2}{3}).

With some restriction on a this means:

\sin(a)=\frac{2}{3}

We need to find \tan(a).

\sin^2(a)+\cos^2(a)=1 is a Pythagorean Identity I will use to find the cosine value and then I will use that the tangent function is the ratio of sine to cosine.

(\frac{2}{3})^2+\cos^2(a)=1

\frac{4}{9}+\cos^2(a)=1

Subtract 4/9 on both sides:

\cos^2(a)=\frac{5}{9}

Take the square root of both sides:

\cos(a)=\pm \sqrt{\frac{5}{9}}

\cos(a)=\pm \frac{\sqrt{5}}{3}

The cosine value is positive because a is a number between -\frac{\pi}{2} and \frac{\pi}{2} because that is the restriction on sine inverse.

So we have \cos(a)=\frac{\sqrt{5}}{3}.

This means that \tan(a)=\frac{\frac{2}{3}}{\frac{\sqrt{5}}{3}}.

Multiplying numerator and denominator by 3 gives us:

\tan(a)=\frac{2}{\sqrt{5}}

Rationalizing the denominator by multiplying top and bottom by square root of 5 gives us:

\tan(a)=\frac{2\sqrt{5}}{5}

Let's continue on to letting b=\cos^{-1}(\frac{1}{7}).

Let's go ahead and say what the restrictions on b are.

b is a number in between 0 and \pi.

So anyways b=\cos^{-1}(\frac{1}{7}) implies \cos(b)=\frac{1}{7}.

Let's use the Pythagorean Identity again I mentioned from before to find the sine value of b.

\cos^2(b)+\sin^2(b)=1

(\frac{1}{7})^2+\sin^2(b)=1

\frac{1}{49}+\sin^2(b)=1

Subtract 1/49 on both sides:

\sin^2(b)=\frac{48}{49}

Take the square root of both sides:

\sin(b)=\pm \sqrt{\frac{48}{49}

\sin(b)=\pm \frac{\sqrt{48}}{7}

\sin(b)=\pm \frac{\sqrt{16}\sqrt{3}}{7}

\sin(b)=\pm \frac{4\sqrt{3}}{7}

So since b is a number between 0 and \pi, then sine of this value is positive.

This implies:

\sin(b)=\frac{4\sqrt{3}}{7}

So \tan(b)=\frac{\sin(b)}{\cos(b)}=\frac{\frac{4\sqrt{3}}{7}}{\frac{1}{7}}.

Multiplying both top and bottom by 7 gives:

\frac{4\sqrt{3}}{1}= 4\sqrt{3}.

Let's put everything back into the first mentioned identity.

\tan(a-b)=\frac{\tan(a)-\tan(b)}{1+\tan(a)\tan(b)}

\tan(a-b)=\frac{\frac{2\sqrt{5}}{5}-4\sqrt{3}}{1+\frac{2\sqrt{5}}{5}\cdot 4\sqrt{3}}

Let's clear the mini-fractions by multiply top and bottom by the least common multiple of the denominators of these mini-fractions. That is, we are multiplying top and bottom by 5:

\tan(a-b)=\frac{2 \sqrt{5}-20\sqrt{3}}{5+2\sqrt{5}\cdot 4\sqrt{3}}

\tan(a-b)=\frac{2\sqrt{5}-20\sqrt{3}}{5+8\sqrt{15}}

4 0
3 years ago
Can someone help me out please I don’t get this
expeople1 [14]
I think the answer is three


i did 9x-1=-5x+41 and i got 3
8 0
3 years ago
18÷6 solve it<br><br><br>answer:​
Oduvanchick [21]

Answer:3 is your answer

Step-by-step explanation:

3 x 6 = 18

8 0
2 years ago
What is the area of the figure below?
Sergeeva-Olga [200]

Hint: Try using the Pythagorean thereom to solve it.

3 0
3 years ago
Other questions:
  • A square has a length of 13m, find its area A. 1699m² B. 169m² C. 196m² D. 169m² I will mark you as brainliest
    10·2 answers
  • A 6 inch personal pizza has 590 calories, with 240 of those from fat. A 16 inch pizza is cut into 8 slices. Estimate the number
    10·1 answer
  • Find the distance between the two points (8, 3) and (0, -3)
    9·2 answers
  • I need number 2. someone please help!
    11·1 answer
  • Fernando has a prime number of books between 21 and 30 he says that if he takes 4of the books away he will be able to place the
    7·1 answer
  • Ten less than a number is at least -8. Solve the inequality.
    8·1 answer
  • Would you rather have many good friends or one very best friend?
    13·2 answers
  • Function or not a function?
    12·1 answer
  • If p(x)=3x+1, what is the value of p(-2) ? *
    5·2 answers
  • For the vertical motion model h(t)=-16t^2+54t+3, identify the maximum height reached by an object and the amount of time the obj
    8·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!