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3 years ago

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in seans fish tank, there are 6 times as many goldfish as there are guppies.there are a total of 21 fish in tje tank. how many m

ore goldfish are there than guppies?

1 answer:

Andrei [34K]3 years ago

6 0

There are 126 more goldfish then guppies.

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I really need help pls helppp meee

zhenek [66]

Answer:

2.50t + 350 = 3t + 225

Step-by-step explanation:

Let t represent the number of tickets that each class needs to sell so that the total amount raised is the same for both classes.

One class is selling tickets for $2.50 each and has already raised $350. This means that the total amount that would be raised from selling t tickets is

2.5t + 350

The other class is selling tickets for $3.00 each and has already raised $225. This means that the total amount that would be raised from selling t tickets is

3t + 225

Therefore, for the total costs to be the same, the number of tickets would be

2.5t + 350 = 3t + 225

8 0

2 years ago

Read 2 more answers

Keith exercises x hours a week. Troy exercises three hours less than Keith and Joe exercises two times more than Troy. Which exp

muminat

If you would like to know which expression represents the amount of time Joe exercises, you can calculate this using the following steps:

Keith ... x hours a week
Troy ... three hours less than Keith: x - 3
Joe ... two times more than Troy: 2 * (x - 3)

The correct result would be D) 2 * (x - 3).

7 0

3 years ago

Read 2 more answers

Help please I don’t understand it show work

melomori [17]

Step-by-step explanation:

Here you solve for length width and height, which multiplied equal volume. The only constant you have is that the width of the prism is 1/3 of its length.

WIDTH: 3 centimeters

LENGTH: Since the width is 1/3 of the length, 3 is 1/3 of something. So divide 3 by 1/3 to get 9. You can also just multiply 3 by 3.

HEIGHT: The height is half of the width, which is 3. Therefore 3 divided by 2 is 1.5.

Now multiply the values. 3 multiplied by 9 multiplied by 1.5

The answer is 40.5

CENTIMETERS!!!

DO NOT FORGET THE UNIT

3 0

3 years ago

Read 2 more answers

Can some please help??

Anvisha [2.4K]

Answer: it would be B or C

Step-by-step explanation: Hope this helps :)

8 0

2 years ago

Read 2 more answers

A university found that 20% of its students withdraw without completing the introductory statistics course. Assume that 20 stude

EleoNora [17]

Answer:

a) $P(X \leq 2)= P(X=0)+P(X=1)+P(X=2)$

And we can use the probability mass function and we got:

$P(X=0)=(20C0)(0.2)^0 (1-0.2)^{20-0}=0.0115$

$P(X=1)=(20C1)(0.2)^1 (1-0.2)^{20-1}=0.0576$

$P(X=2)=(20C2)(0.2)^2 (1-0.2)^{20-2}=0.1369$

And adding we got:

$P(X \leq 2)=0.0115+0.0576+0.1369 = 0.2061$

b) $P(X=4)=(20C4)(0.2)^4 (1-0.2)^{20-4}=0.2182$

c) $P(X>3) = 1-P(X \leq 3) = 1- [P(X=0)+P(X=1)+P(X=2)+P(X=3)]$

$P(X=0)=(20C0)(0.2)^0 (1-0.2)^{20-0}=0.0115$

$P(X=1)=(20C1)(0.2)^1 (1-0.2)^{20-1}=0.0576$

$P(X=2)=(20C2)(0.2)^2 (1-0.2)^{20-2}=0.1369$

$P(X=3)=(20C3)(0.2)^3 (1-0.2)^{20-3}=0.2054$

And replacing we got:

$P(X>3) = 1-[0.0115+0.0576+0.1369+0.2054]= 1-0.4114= 0.5886$

d) $E(X) = 20*0.2= 4$

Step-by-step explanation:

Previous concepts

The binomial distribution is a "DISCRETE probability distribution that summarizes the probability that a value will take one of two independent values under a given set of parameters. The assumptions for the binomial distribution are that there is only one outcome for each trial, each trial has the same probability of success, and each trial is mutually exclusive, or independent of each other".

Solution to the problem

Let X the random variable of interest, on this case we now that:

$X \sim Binom(n=20, p=0.2)$

The probability mass function for the Binomial distribution is given as:

$P(X)=(nCx)(p)^x (1-p)^{n-x}$

Where (nCx) means combinatory and it's given by this formula:

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

Part a

We want this probability:

$P(X \leq 2)= P(X=0)+P(X=1)+P(X=2)$

And we can use the probability mass function and we got:

$P(X=0)=(20C0)(0.2)^0 (1-0.2)^{20-0}=0.0115$

$P(X=1)=(20C1)(0.2)^1 (1-0.2)^{20-1}=0.0576$

$P(X=2)=(20C2)(0.2)^2 (1-0.2)^{20-2}=0.1369$

And adding we got:

$P(X \leq 2)=0.0115+0.0576+0.1369 = 0.2061$

Part b

We want this probability:

$P(X=4)$

And using the probability mass function we got:

$P(X=4)=(20C4)(0.2)^4 (1-0.2)^{20-4}=0.2182$

Part c

We want this probability:

$P(X>3)$

We can use the complement rule and we got:

$P(X>3) = 1-P(X \leq 3) = 1- [P(X=0)+P(X=1)+P(X=2)+P(X=3)]$

$P(X=0)=(20C0)(0.2)^0 (1-0.2)^{20-0}=0.0115$

$P(X=1)=(20C1)(0.2)^1 (1-0.2)^{20-1}=0.0576$

$P(X=2)=(20C2)(0.2)^2 (1-0.2)^{20-2}=0.1369$

$P(X=3)=(20C3)(0.2)^3 (1-0.2)^{20-3}=0.2054$

And replacing we got:

$P(X>3) = 1-[0.0115+0.0576+0.1369+0.2054]= 1-0.4114= 0.5886$

Part d

The expected value is given by:

$E(X) = np$

And replacing we got:

$E(X) = 20*0.2= 4$

3 0

3 years ago