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3 years ago

Which operations is the following set closed under: {... , -3, -1, 1, 3, ...}?

2 answers:

6 0

I'd say it's closed for multiplication and division.
Any member of the set, when multiplied or divided by
any other one, produces another member of the set.

Ganezh [65]3 years ago

5 0

Not addition, since $-1+1=0$ and 0 doesn't belong to the set.

Not subtraction, since $1-1=0$ .

It is closed under multiplication. The set appears to contain all non-zero multiples of 3.

Not division, since dividing some of the numbers results in rationals which do not belong to the set.

What other operations are you supposed to consider?

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Clark has a box of nickels and dimes that totals $1.90. there are a total of 27 coins. how many nickels and dimes does he have?

Andrej [43]

$0.05(n) + $0.10(d) = $1.90
n + d = 27
n + d - d =27 - d
n = 27 - d

$0.05(27-d) + $0.10(d) = $1.90
1.35 - 0.05d + 0.10d = $1.90
1.35 +0.05d = $1.90
1.35 - 1.35 +0.05d = $1.90 -1.35
0.05d = 0.55
0.05d/0.05 = 0.55/0.05
d = 11

n = 27 - 11
n = 16

$0.05(16) + $0.10(11) = $1.90
$0.80 + $1.10 = $1.90
$1.90 = $1.90

4 0

3 years ago

am i the only one that's confused? i don't get this and neither does my older sister! please tell me if u get it! :0

katovenus [111]

Answer:

I believe the answer is C. I'd have to work this out on paper to be certain, but from what i worked out mentally, i got C. lol

Step-by-step explanation:

3 0

2 years ago

Read 2 more answers

Ivan has 4 hours of Music on his MP3 player Jazz makes up 1/6 of the total time how many hours of jazz are on Ivan's MP3 player

Crank

So theres 4 hours and 60min equals 1 hour, so multiply 4 by 60 to get 240, so theres 240 minutes of time on the mp3. So 1/6 of that total time (240min) was on jazz, so what you do is divide 240 by 6 to get 40, so every 1/6 is 40min. So you could say he spend 40min listening to jazz, or you could say he spent 2/3 of an hour listening to jazz

5 0

2 years ago

Using a proportion, what can you infer about the number of households in her town that have more than three children?

eduard

Answer:

About 296 households have more than three children.

Step-by-step explanation:

The complete question is:

Carmen used a random number generator to simulate a survey of how many children live in the households in her town. There are 1,346 unique addresses in her town with numbers ranging from zero to five children. The results of 50 randomly generated households are shown below. Children in 50 Households Number of Children Number of Households 0 5 1 11 2 13 3 10 4 9 5 2 Using a proportion, what can you infer about the number of households in her town that have more than three children? About 242 households have more than three children. About 269 households have more than three children. About 296 households have more than three children. About 565 households have more than three children.

Solution:

The data provided for the number of children and number of households is:

Number of Children (X) Number of Households (f (X))

0 5

1 11

2 13

3 10

4 9

5 2

TOTAL 50

Compute the probability of households having more than three children as follows:

P (More than 3 children) = P (4 children) + P (5 children)

$=\frac{9}{50}+\frac{2}{50}$

$=\frac{11}{50}$

$=0.22$

Let the random variable Y be defined as the number of households having more than three children.

The probability of the random variable Y is, p = 0.22.

The entire population, i.e. total number of addresses in Carmen's town with numbers ranging from zero to five children, consists of N = 1,346 households.

Compute the expected number of households having more than three children as follows:

$E(Y) =N\times p$