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3 years ago

Please help !!!!! I need help on this problem please :(

Mathematics

1 answer:

mariarad [96]3 years ago

6 0

Answer:

2/3

Step-by-step explanation:

1. (4/9)^1/2

2. 4/9 + 2/9 = 6/9

3. simplify it gives you 2/3

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At 2 PM, a thermometer reading 80°F is taken outside where the air temperature is 20°F. At 2:03 PM, the temperature reading yiel

Alexeev081 [22]

Use Law of Cooling:
$T(t) = (T_0 - T_A)e^{-kt} +T_A$
T0 = initial temperature, TA = ambient or final temperature

First solve for k using given info, T(3) = 42
$42 = (80-20)e^{-3k} +20 \\ \\ e^{-3k} = \frac{22}{60}=\frac{11}{30} \\ \\ k = -\frac{1}{3} ln (\frac{11}{30})$

Substituting k back into cooling equation gives:
$T(t) = 60(\frac{11}{30})^{t/3} + 20$

At some time "t", it is brought back inside at temperature "x".
We know that temperature goes back up to 71 at 2:10 so the time it is inside is 10-t, where t is time that it had been outside.
The new cooling equation for when its back inside is:
$T(t) = (x-80)(\frac{11}{30})^{t/3} + 80 \\ \\ 71 = (x-80)(\frac{11}{30})^{\frac{10-t}{3}} + 80$
Solve for x:
$x = -9(\frac{11}{30})^{\frac{t-10}{3}} + 80$
Sub back into original cooling equation, x = T(t)
$-9(\frac{11}{30})^{\frac{t-10}{3}} + 80 = 60 (\frac{11}{30})^{t/3} +20$
Solve for t:
$60 (\frac{11}{30})^{t/3} +9(\frac{11}{30})^{\frac{-10}{3}}(\frac{11}{30})^{t/3} = 60 \\ \\ (\frac{11}{30})^{t/3} = \frac{60}{60+9(\frac{11}{30})^{\frac{-10}{3}}} \\ \\ \\ t = 3(\frac{ln(\frac{60}{60+9(\frac{11}{30})^{\frac{-10}{3}}})}{ln (\frac{11}{30})}) \\ \\ \\ t = 4.959$

This means the exact time it was brought indoors was about 2.5 seconds before 2:05 PM

8 0

3 years ago

Please help will give brainliest if I can :)

Paraphin [41]

Answer:

So you take the 172 miles and you divide it by the 3cm that you have and that gives you 57.3 miles. And therefore 1cm would be equal to 57.3

Step-by-step explanation:

7 0

2 years ago

In a recent survey of 25 voters, 17 favor a new city regulation and 8 oppose it. What is the probability that in a random sample

Rasek [7]

Answer:

$P(X=2)=(6C2)(0.68)^2 (1-0.68)^{6-2}=0.0727$

Step-by-step explanation:

1) 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".

2) Solution to the problem

The probability in favor of the regulation based on the recent survey is:

$p = \frac{17}{25}=0.68$

Let X the random variable of interest "Number of favor respondents about the regulation", on this case we now that:

$X \sim Binom(n=6, p=0.68)$

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:

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

And we want to find this probability:

$P(X=2)=(6C2)(0.68)^2 (1-0.68)^{6-2}=0.0727$

If we use X= "Number of respondednts opposed to the regulation we got the same answer", but on this case p = 1-0.68=0.32, and we want this probability:

$P(X=4)=(6C4)(0.32)^4 (1-0.32)^{6-4}=0.0727$

6 0

3 years ago

Help me on this pleaseee

lisabon 2012 [21]

Answer:

Bolded below are the answers

Step-by-step explanation:

4568 ÷ 8

(4000 ÷ 8) + (560 ÷ 8) + (8 ÷ 8)

500 + 70 + 1

571

Hope this helps!

8 0

2 years ago

Read 2 more answers

The taxi costs $2.25 for the first mile plus 15cents for each additional tenth of a mile. For a 5.2 mile trip, Eric payed $10 an

Verizon [17]

2.25 for the first mile. That leaves 4.2 miles.

4 * 0.1 = 0.4

0.15 * 4 = $6.00

0.15 * 2 = 0.3

$6.30 + $2.25 = $8.55

$10.00 - $8.55 = $1.45

The driver's tip was $1.45.

7 0

3 years ago