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3 years ago

If you roll two number cubes, what is the probability of their sum being seven or higher?

Mathematics

2 answers:

DIA [1.3K]3 years ago

8 0

27 rolls of being 7 or higher

marin [14]3 years ago

3 0

1) Number of possible outcomes when 2 cubes are rolled = n^2 = 6^2 = 36
Possible outcomes for a sum = 7 are 6 as detailed below
(1,6) (2,5) (3,4) (4,3) (5,2) (6,1) = 6
Possible outcomes for a sum = 11 are 2 as detailed below
(5,6) (6,5) = 2
Required probability = 6/36 + 2/36 = 8/36 = 0.22222

2) Number of possible outcomes when a cube and a coin are tossed = m*n = 6*2 = 12
Possible outcomes for a tail and 6 = 1
Required probability = 1/12 = 0.08333

3) Possible outcomes for a sum =3 are 2 as detailed below
(1,2) (2,1) = 2
Possible outcomes for a sum = 8 are 5 as detailed below
(2,6) (3,5) (4,4) (5,3) (6,2) = 5
Required probability = 2/36 + 5/36 = 7/36 = 0.19444

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Robert ran 3 1/3 mph for 3/4 of an hour. How far did he run?

matrenka [14]

Answer:

2 ½ miles

Explanation:

mph = miles per hour, which means that if robert had run for the full 1 hour, he would have run 3 ⅓ miles.

however, since he only ran for ¾ of an hour, which is equal to 0.75, we can multiply the 3 ⅓ miles by 0.75 to get 2.5 or 2 ½ miles.

i hope this helps! :D

7 0

3 years ago

Danielle and David each have a job. Danielle earns $15 an hour. She also receives a $50 weekly bonus. Danielle wrote an equation

S_A_V [24]

For starters, create an equation to show David's earnings. We can do this using Danielle's as a basis, which is set up as y=(# of hours)x+(bonus). This gives us y=12x+80. Now, as we need both their ys to be equal, we just set both equations equal to each other, making 15x+50=12x+80. Now, we solve for x, starting with 15x+50=12x+80, subtracting 12x from both sides to get 3x+50=80, subtracting 50 from both sides to get 3x=30, and dividing three from both sides to get x=10. To check, we just plug in our answer to both equations and see if the ys match up. With Danielle's equation, we get y=15(10)+50=150+50=200 and with David's equation, we get y=12(10)+80=120+80=200, proving that our answer is correct.

5 0

3 years ago

Read 2 more answers

Assume the average height for American women is 64 inches with a standard deviation of 2 inches. A sorority on campus wonders if

satela [25.4K]

Answer:

a) s = 0.4

b) Z = 2.5

c) 99th percentile.

d) The larger sample size would lead to a smaller margin of error, which would lead to a higher z-score and a increased percentile.

Step-by-step explanation:

To solve this question, we need to understand the normal probability distribution and the central limit theorem.

Normal Probability Distribution:

Problems of normal distributions can be solved using the z-score formula.

In a set with mean $\mu$ and standard deviation $\sigma$ , the z-score 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 p-value, we get the probability that the value of the measure is greater than X.

Central Limit Theorem

The Central Limit Theorem establishes that, for a normally distributed random variable X, with mean $\mu$ and standard deviation $\sigma$ , the sampling distribution of the sample means with size n can be approximated to a normal distribution with mean $\mu$ and standard deviation $s = \frac{\sigma}{\sqrt{n}}$ .

For a skewed variable, the Central Limit Theorem can also be applied, as long as n is at least 30.

Assume the average height for American women is 64 inches with a standard deviation of 2 inches

This means that $\mu = 64, \sigma = 2$

A) Calculate the standard error for the distribution of means.

Sample of 25 means that $n = 25$ , so $s = \frac{2}{\sqrt{25}} = 0.4$ .

B) Calculate the z statistic for the sorority group.

Sample mean of 65 means that $X = 65$ .

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

By the Central Limit Theorem

$Z = \frac{X - \mu}{0.4}$

$Z = \frac{65 - 64}{0.4}$

$Z = 2.5$

C) What is the approximate percentile for this sample? Enter as a whole number.

Z = 2.5 has a p-value of 0.9938, so 0.99*100 = 99th percentile.

D) If the sorority actually had 36 members (still with an average of 65 inches), would you expect the percentile value to increase or decrease? why?

The larger sample size would lead to a smaller margin of error, which would lead to a higher z-score and a increased percentile.

3 0

3 years ago

Fins the product of 5/12 And 3/8

Kamila [148]

Answer:

Step-by-step explanation:

( 5/12) × (3/8) =(5×3)/(12×8) = 5/32

4 0

3 years ago

(( I will give 25 points and brainy from right answers (Please answer all!!) )

sleet_krkn [62]

1. C. Concave pentagon

2. A. 1620°

b/c (11 - 2) × 180 = 1620

3. B. 165°

b/c (24 - 2) × 180 ÷ 24 = 165

4. A. 160°

b/c (18 - 2) × 180 ÷ 18 = 160

6 0

3 years ago