Translate the sentence into a mathematical expression: “Twice x is 5”

A crew is made up of 12 men the rest are women. 40% of the crew are men. How many women are in the crew.

4vir4ik [10]

Answer:

Step-by-step explanation:

let nr of women be x

12 men represents 40%

?women represents 100%

12*100/40=30

30 women and 12 men are in the crew

8 0

3 years ago

The number of violent crimes committed in a day possesses a distribution with a mean of 2.8 crimes per day and a standard deviat

Deffense [45]

Answer:

The distribution is approximately normal with mean = 2.8 and standard error = 0.4

Step-by-step explanation:

We are given;

Mean; μ = 2.8

Standard deviation; σ = 4

Sample size; n = 100

Now, the central limit theorem states that the sample mean with a sample size(n) from a population mean (μ) and population standard deviation(σ) will, for large value of n, have an approximately normal distribution with mean μ and standard error as (σ/√n)

The sample size is 100 and thus it's very large because it's bigger than minimum of 30 for approximate distribution.

Thus, SE = (σ/√n) = 4/√100 = 4/10 = 0.4

Thus,from the central limit theorem I described, we can say that the distribution is approximately normal with mean = 2.8 and standard error = 0.4

8 0

3 years ago

How many positive four-digit integers have the three digits the same and a different fourth digit (in some order)

malfutka [58]

Answer:

81 * 4 = 324.

Step-by-step explanation:

There are 81 * 4 = 324 such integers.

There are 9000 four-digit integers from 1000 to 9999. Let’s refer to the digit that occurs three times as the triplet and the digit that occurs once as the singleton.

In the first (most significant) position there are 9 possible values for the singleton, 1 through 9. In each case there are also 9 possible values for the triplet. For example if the singleton was a 1, the triplets could be anything but a 1: 1000, 1222, 1333, …, 1999. So there are 9 * 9 = 81 cases with the singleton in the first position.

A singleton in the second position can have 10 possible values, 0 through 9. If it’s a 0 there are 9 possible values for the triplet: 1011, 2022, 3033, …, 9099. If it’s anything else there are only 8 possible values for the triplet since the triplet cannot be 0: 2122, 3133, 4144, …, 9199. So there are 9 + (8 * 9) = 81 cases with the singleton in the second position.

The third and fourth positions work just like the second. So the grand total is 81 * 4 = 324.

If you plot the 9000 four-digit integers as a 100 x 90 grid of squares and color the integers with three same digits in red, an interesting pattern occurs:

There are 81 * 4 = 324 such integers.

There are 9000 four-digit integers from 1000 to 9999. Let’s refer to the digit that occurs three times as the triplet and the digit that occurs once as the singleton.

In the first (most significant) position there are 9 possible values for the singleton, 1 through 9. In each case there are also 9 possible values for the triplet. For example if the singleton was a 1, the triplets could be anything but a 1: 1000, 1222, 1333, …, 1999. So there are 9 * 9 = 81 cases with the singleton in the first position.

A singleton in the second position can have 10 possible values, 0 through 9. If it’s a 0 there are 9 possible values for the triplet: 1011, 2022, 3033, …, 9099. If it’s anything else there are only 8 possible values for the triplet since the triplet cannot be 0: 2122, 3133, 4144, …, 9199. So there are 9 + (8 * 9) = 81 cases with the singleton in the second position.

The third and fourth positions work just like the second. So the grand total is 81 * 4 = 324.

If you plot the 9000 four-digit integers as a 100 x 90 grid of squares and color the integers with three same digits in red, an interesting pattern occurs:

(If you zoom in, the four-digit number is printed inside each red square - not sure whether or not that will come through after Quora processes the image.)

Hope this helps!

Brain-List?