Please help me solve for n

Sergio got 80% on a test. He answers 24 questions right. How many questions are on the test?

miskamm [114]

24 divided by 80= 0.3
24/30 there were 30 questions on the test and he got 24 right

8 0

3 years ago

A coin is tossed 8 times. What is the probability of getting all heads? Express your answer as a simplified fraction or a decima

kumpel [21]

Answer:

The probability of getting all heads is $\frac{1}{256}$ .

Step-by-step explanation:

For each time the coin is tossed, there are only two possible outcomes. Either it is heads, or it is not. So we use the binomial probability distribution to solve this problem.

Binomial probability distribution

The binomial probability is the probability of exactly x successes on n repeated trials, and X can only have two outcomes.

$P(X = x) = C_{n,x}.p^{x}.(1-p)^{n-x}$

In which $C_{n,x}$ is the number of different combinations of x objects from a set of n elements, given by the following formula.

$C_{n,x} = \frac{n!}{x!(n-x)!}$

And p is the probability of X happening.

In this problem, we have that:

A coin is tossed 8 times. This means that $n = 8$

In each coin toss, heads or tails are equally as likely. So $p = \frac{1}{2}$

What is the probability of getting all heads?

This is $P(X = 8)$

$P(X = x) = C_{n,x}.p^{x}.(1-p)^{n-x}$

$[tex]P(X = 8) = C_{8,8}*(\frac{1}{2})^{8}*(1 - \frac{1}{2})^{0}$ = $\frac{1}{256}$

The probability of getting all heads is $\frac{1}{256}$ .

7 0

3 years ago

In 1967 a 30-second super bowl commercial cost 40,000. In 2000 a 30-second commercial cost 1,800,000. What was the percent of ch

Vinil7 [7]

4400% increase

1800000-40000/40000 = x/100

1760000/40000 = x/100

176*25/4*25 = x/100

X= 4400% increase

4 0

3 years ago

The ratio of chaperones to students on a field trip to New York city is 2to11.If there are 297 students on the trip how many Cha

Rus_ich [418]

Answer:

54 chaperones

Step-by-step explanation:

The basic idea behind this kind of question is that you want to keep the proportions equal. When there are 11 students, there are 2 chaperones. If there are now 297 students, how many chaperones must there be keep the proportions equal?

When answering this sort of question, you should construct an equation in which the basic ratio is equal to the proportions you're interested in. In this case:

2 chaperones / 11 students = X chaperones / 297 students

To find the value of X, you then cross-multiply and solve for X.

Cross-multiplying means that you multiply the numerator (top) on one side by the denominator (bottom) on the other, and vice versa.

Here,

2 chaperones x 297 students = 11 students x X chaperones

You then solve for X.

First, multiply the left side:

594 = 11X

Now, divide 594 / 11 to solve for X.

X = 54.

Because X stood for the number of chaperones, the answer is 54 chaperones.

8 0

3 years ago

Read 2 more answers

On Sunday, Jesse played basketball for 1 2/3 hours. How many total hours did he play basketball on Saturday and Sunday

Naddik [55]

I believe the answer is 3 because 1 ⅔ plus 1 ⅔ equals 3 hours so Jesse played basketball.

3 0

3 years ago