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3 years ago

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Elena and Jada are 25 miles apart when they start moving toward each other. Elena runs at a constant speed of 6 mph and Jada wal

ks at a constant speed of 4 mph. How long does it take for Jada and Elena to meet?

1 answer:

Setler [38]3 years ago

3 0

<u>Answer:</u>

The Time taken by Elena and Jade to meet up is 2.5 hours

<u>Explanation:</u>

Given,

Elena moves with a speed of 6mph while Jada walks at a speed of 4 mph

Also, Distance can be calculated by the formula

$Distance = Speed * Time$

To find out the Total speed, i.e., speed of both Elena and Jada as both of them are walking in opposite direction we should add the speed of both the persons, if in same direction we should subtract the values

Here it will be: $6 + 4$ = 10mph

Distance apart is given as 25 miles. Substituting the values,

$Distance = Speed * Time$

25 = $10 * time$

Time = 25/10

Time = 2.5 hour

Hence, It will take 2.5 hours to meet up.

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According to a survey, 65% of murders committed last year were cleared by arrest or exceptional means. Fifty murders committed

monitta

Answer:

a) $P(X=41)=(50C41)(0.65)^{41} (1-0.65)^{50-41}=0.00421$

b) $P(X=36)=(50C36)(0.65)^{36} (1-0.65)^{50-36}=0.0714$

$P(X=37)=(50C37)(0.65)^{37} (1-0.65)^{50-37}=0.0502$

$P(X=38)=(50C38)(0.65)^{38} (1-0.65)^{50-38}=0.0319$

And adding these values we got:

$P(36 \leq X \leq 38)= 0.1535$

c) We can find the expected value given by:

$E(X) = np =50*0.65 = 32.5$

And the standard deviation would be:

$\sigma = \sqrt{np(1-p)} \sqrt{50*0.65*(1-0.65)}= 3.373$

We can use the approximation to the normal distribution and we have at leat 95% of the data within 2 deviations from the mean. And the lower limit for this case would be:

$\mu -2\sigma = 32.5- 2*3.373 = 25.75$

And then we can consider a value of 18 as unusual lower for this case.

Step-by-step explanation:

Let X the random variable of interest "number cleared by arrest or exceptional", on this case we can model this variable with this distribution:

$X \sim Binom(n=50, p=0.65)$

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:

$P(X=41)=(50C41)(0.65)^{41} (1-0.65)^{50-41}=0.00421$

Part b

We want this probability:

$P(36 \leq X \leq 38)$

We can find the individual probabilities:

$P(X=36)=(50C36)(0.65)^{36} (1-0.65)^{50-36}=0.0714$

$P(X=37)=(50C37)(0.65)^{37} (1-0.65)^{50-37}=0.0502$

$P(X=38)=(50C38)(0.65)^{38} (1-0.65)^{50-38}=0.0319$

And adding these values we got:

$P(36 \leq X \leq 38)= 0.1535$

Part c

We can find the expected value given by:

$E(X) = np =50*0.65 = 32.5$

And the standard deviation would be:

$\sigma = \sqrt{np(1-p)} \sqrt{50*0.65*(1-0.65)}= 3.373$

We can use the approximation to the normal distribution and we have at leat 95% of the data within 2 deviations from the mean. And the lower limit for this case would be:

$\mu -2\sigma = 32.5- 2*3.373 = 25.75$

And then we can consider a value of 18 as unusual lower for this case.

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3 years ago

Brian saved 30% of the money he earned.If brain earned $260,how much did he save?

mina [271]

30/100 = 0.30

0.30 * 260 = 78

He saved $78.

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3/5 + 3/7 = it a Fraction problem

Rudik [331]

<span>3/5 + 3/7
Multiply the denominator until they have the same common denominator.
21/35 + 15/35
Add the numerators but NOT the denominators
Final Answer: 36/35 or 1 1/35</span>

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3 years ago

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During a scuba dive, Lainey descended to a point 19 feet below the ocean surface. She continued her descent at a rate of 25 feet

Leno4ka [110]

Answer:

$25t+19\leq 144$

$t\leq5$

The number of minutes she can continue to descend if she does not want to reach a point more than 144 feet below the ocean surface is <u>at most 5 minutes.</u>

Step-by-step explanation:

Given:

Initial depth of the scuba dive = 19 ft

Rate of descent = 25 ft/min

Maximum depth to be reached = 144 ft

Now, after 't' minutes, the depth reached by the scuba dive is equal to the sum of the initial depth and the depth covered in 't' minutes moving at the given rate.

Framing in equation form, we get:

Total depth = Initial Depth + Rate of descent × Time

Total depth = $19+25t$

Now, as per question, the total depth should not be more than 144 feet. So,

$\textrm{Total depth}\leq 144\ ft\\\\19+25t\leq 144\\\\or\ 25t+19\leq 144$

Solving the above inequality for time 't', we get:

$25t+19\leq 144\\\\25t\leq 144-19\\\\25t\leq 125\\\\t\leq \frac{125}{25}\\\\t\leq 5\ min$

Therefore, the number of minutes she can continue to descend if she does not want to reach a point more than 144 feet below the ocean surface is at most 5 minutes.

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3 years ago

What is the exact circumference of the circle?

Arlecino [84]

I am pretty sure it is 180 degrees

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