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aleksklad [387]
3 years ago
11

Which equation would be the easiest to solve first by using the substitution method? EXPLAIN WHY

Mathematics
1 answer:
Arlecino [84]3 years ago
6 0

Answer:

Equation 2: x - 2y = 1

Step-by-step explanation:

The equations easiest to use substitution are the ones that have the variable multiplied by one, as in the case of Eq. 2 where x is 1x, so if you substitute a zero for x, we know that y has to be -1/2 for the equation to be true.  Furthermore, if you substitute a 0 for y you automatically know that x = 1.

If you try to substitute anything for x in equation 1, let's say x = 1, you still have to multipy by 3, then the rest of the problem would be more steps.

You might be interested in
Identify the property used in this equation: (–2) + 6 + 1 = 1 + 6 + (–2)
ruslelena [56]
(-2) + 6 + 1 = 1 + 6 + (-2)
-2 + 7 = 7 - 2
5 = 5
7 0
4 years ago
The elevator maximum capacity is 1,000 pounds. Alex weighs 165 pounds and his helper Joan weighs 145 pounds. They have 50 pound
SVEN [57.7K]

Answer:

13

Step-by-step explanation:

If Alex and Joan's combined weight is 310, keep that in mind for each trip.

(1000-310)/50=answer

100-310= 690

690/50= 13.8

But you can't have a partial box, so it'll be only 13. You can't round up because then the total weight will be 10 over.

3 0
3 years ago
The amount of water in a bottle is approximately normally distributed with a mean of 2.55 liters with a standard deviation of 0.
Natalka [10]

Answer:

a) P(X

b) P(\bar X

c) P(\bar X

d) For part a we are just finding the probability that an individual bottle would have a value of 2.52 liters or less. So we can't compare the result of part a with the results for parts b and c.

If we see part b and c are similar but the difference it's on the sample size for part b we just have a sample size 4 and for part c we have a sample size of 25. The differences are because we have a higher standard error for part b compared to part c.

Step-by-step explanation:

Normal distribution, is a "probability distribution that is symmetric about the mean, showing that data near the mean are more frequent in occurrence than data far from the mean".

The Z-score is "a numerical measurement used in statistics of a value's relationship to the mean (average) of a group of values, measured in terms of standard deviations from the mean".  The letter \phi(b) is used to denote the cumulative area for a b quantile on the normal standard distribution, or in other words: \phi(b)=P(z

Let X the random variable that represent the amount of water in a bottle of a population, and for this case we know the distribution for X is given by:

X \sim N(2.55,0.035)

a. What is the probability that an individual bottle contains less than 2.52 liters?

We are interested on this probability

P(X

And the best way to solve this problem is using the normal standard distribution and the z score given by:

z=\frac{x-\mu}{\sigma}

If we apply this formula to our probability we got this:

P(X

And in order to find these probabilities we can find tables for the normal standard distribution, excel or a calculator.  

P(X

b. If a sample of 4 bottles is selected, what is the probability that the sample mean amount contained is less than 2.52 liters? (Round to three decimal places as noeded)

And let \bar X represent the sample mean, the distribution for the sample mean is given by:

\bar X \sim N(\mu,\frac{\sigma}{\sqrt{n}})

On this case  \bar X \sim N(2.55,\frac{0.035}{\sqrt{4}})

The z score on this case is given by this formula:

z=\frac{\bar x-\mu}{\frac{\sigma}{\sqrt{n}}}

And if we replace the values that we have we got:

z=\frac{2.52-2.55}{\frac{0.035}{\sqrt{4}}}=-1.714

For this case we can use a table or excel to find the probability required:

P(\bar X

c. If a sample of 25 bottles is selected, what is the probability that the sample mean amount contained is less than 2.52 liters? (Round to three decimal places as needed.)

The z score on this case is given by this formula:

z=\frac{\bar x-\mu}{\frac{\sigma}{\sqrt{n}}}

And if we replace the values that we have we got:

z=\frac{2.52-2.55}{\frac{0.035}{\sqrt{25}}}=-4.286

For this case we can use a table or excel to find the probability required:

P(\bar X

d. Explain the difference in the results of (a) and (c)

For part a we are just finding the probability that an individual bottle would have a value of 2.52 liters or less. So we can't compare the result of part a with the results for parts b and c.

If we see part b and c are similar but the difference it's on the sample size for part b we just have a sample size 4 and for part c we have a sample size of 25. The differences are because we have a higher standard error for part b compared to part c.  

3 0
3 years ago
K +-23 = -100<br>help me
Alex_Xolod [135]

Answer:

-77

Step-by-step explanation:

-77 + -23 = -100

4 0
3 years ago
At 4pm the temperature started to change drastically each hour for 3 hours the temperature decreased by 7°F wich expression best
soldi70 [24.7K]

Answer:

(-1)(7+7+7)

Step-by-step explanation:

given data

change drastically each hour =  3 hour

temperature decreased = 7°F

solution

we get some option that are

7+7+7

7+7+7+7

(-1)(7+7+7)

(-7)+(-7)+(-7)+(-7)

  • First, as the temperature decreases, it means that the final answer is negative, or that the change must be multiplied by -1.
  • The temperature varies from 7. to every hour. There is also the question of whether the temperature changes for 3 hours. Hence the temperature change is from 3 7, or 7 + 7 + 7.
  • In the last we add -1 from the beginning because this is a negative temperature change, the answer is (-1) (7 + 7 + 7)

5 0
4 years ago
Read 2 more answers
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