Ask question

Ask question

All categories

vladimir2022 [97]

3 years ago

14

A math class has 5 girls and 5 boys in the seventh grade and 5 girls and 7 boys in eight grade. What is the probability that the

students selected are both girls

1 answer:

saw5 [17]3 years ago

4 0

Answer:

Step-by-step explanation:

I assume you mean consecutive picks without replacement.

There are 10 girls and 22 students so

P(GG)=(10/22)(9/21)

P(GG)=90/462

P(GG)=15/77

You might be interested in

5) Two machines M1, M2 are used to manufacture resistors with a design

Basile [38]

Answer:

Since M1 has the higher probability of being in the desired range, we choose M1.

Step-by-step explanation:

Problems of normally distributed samples are solved using the z-score formula.

In a set with mean $\mu$ and standard deviation $\sigma$ , the zscore of a measure X is given by:

$Z = \frac{X - \mu}{\sigma}$

The Z-score measures how many standard deviations the measure is from the mean. After finding the Z-score, we look at the z-score table and find the p-value associated with this z-score. This p-value is the probability that the value of the measure is smaller than X, that is, the percentile of X. Subtracting 1 by the pvalue, we get the probability that the value of the measure is greater than X.

Two machines M1, M2 are used to manufacture resistors with a design specification of 1000 ohm with 10% tolerance.

So we need the machines to be within 1000 - 0.1*1000 = 900 ohms and 1000 + 0.1*1000 = 1100 ohms.

For each machine, we need to find the probabilty of the machine being in this range. We choose the one with the higher probability.

M1:

Resistors of M1 are found to follow normal distribution with mean 1050 ohm and standard deviation of 100 ohm. This means that $\mu = 1050, \sigma = 100$

The probability is the pvalue of Z when X = 1100 subtracted by the pvalue of Z when X = 900. So

X = 1100

$Z = \frac{X - \mu}{\sigma}$

$Z = \frac{1100 - 1050}{100}$

$Z = 0.5$

$Z = 0.5$ has a pvalue of 0.6915.

X = 900

$Z = \frac{X - \mu}{\sigma}$

$Z = \frac{900 - 1050}{100}$

$Z = -1.5$

$Z = -1.5$ has a pvalue of 0.0668

0.6915 - 0.0668 = 0.6247.

M1 has a 62.47% probability of being in the desired range.

M2:

M2 are found to follow normal distribution with mean 1000 ohm and standard deviation of 120 ohm. This means that $\mu = 1000, \sigma = 120$

X = 1100

$Z = \frac{X - \mu}{\sigma}$

$Z = \frac{1100 - 1000}{120}$

$Z = 0.83$

$Z = 0.83$ has a pvalue of 0.7967.

X = 900

$Z = \frac{X - \mu}{\sigma}$

$Z = \frac{900 - 1000}{120}$

$Z = -0.83$

$Z = -0.83$ has a pvalue of 0.2033

0.7967 - 0.2033 = 0.5934

M2 has a 59.34% probability of being in the desired range.

Since M1 has the higher probability of being in the desired range, we choose M1.

8 0

3 years ago

I Need Help On This

disa [49]

Answer:

The first blank: not equal

The 2nd blank: not right triangle (it's acute triangle)

The 3rd blank: equal

The 4th blank: it's right triangle

Step-by-step explanation:

4^2 = 3^2 + 3^2

<=> 16 = 9 + 9

<=> 16 = 18 ( nonsense)

so triangle LKJ is not right triangle

5^2 = 4^2 + 3^2

<=> 25 = 16 + 9

<=> 25 = 25 ( make sense)

so triangle ABC is right triangle

Done!! :))

6 0

3 years ago

I need help! Please help! SOS

miss Akunina [59]

Answer:

a) 94 degrees lower

b) -17 degrees

Step-by-step explanation:

you should draw a number line to visualize what i'm saying..

basically any number that has a greater value but is negative is obviously lower than a smaller negative value

for example: take -563 that is a lot less than -31 because its farther down the number line

okay to find the answer to question a) you need to obviously find the difference between -29 and 65 to do that you need to count the space in between -29 and 65 on a number line.

There's actually a much easier method just use your common sense and some math: so you can say the distance from 0 to 65 is … 65 and the distance from -29 to 0 is 29 so to find the total distance you add them up and you get your answer! (94)

for b) its even easier you just take the number -29 and add 12 from it to get closer to 0 so to do that you need to subtract 12 to get a smaller number but bigger value on the number line (if you draw this one out it will make sense). And the answer is... -17! I hope this made sense :)

3 0

3 years ago

Which sequence of transformations creates a similar but not congruent triangle?

olya-2409 [2.1K]

The answer is D dilation and reflection

8 0

3 years ago

Read 2 more answers

What’s the value of x in this problem?

Reika [66]

120-58=62
So the x is 62

6 0

4 years ago

Read 2 more answers