I need urgent help and maybe please explain how to do it? I will appreciate it

Mathematics

1 answer:

melisa1 [442]2 years ago

4 0

Answer:

It will take 12.5 days for Alejandra to catch up with Javier and they both will have travelled 800m

Step-by-step explanation:

Alejandra "catching up" implies that they will both have travelled the same distance

Therefore,

Let y represent the distance when Alejandra will catch up with Javier

Since both equations have the same y-value (distance):

24x+500 = 12x+650

24x - 12x = 650 - 500

12x = 150

x = 12.5

It will take 12.5 days for Alejandra to catch up with Javier

Next, put the amount of time into any of the 2 equations to find what the distance is:

24x + 500 = y

24 (12.5) + 500 = y

y = 800

800m is the distance travelled when Alejandra catches up with Javier

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If Colorado spring, Colorado, has 1.2 times as many days of sunshine as Boston, Massachusetts, how many days of sunshine does ea

Crank

C= Colorado B= Boston
C + B = 464
C = 1.2B
Substitute the known value of C from the second equation into the first
C + B = 464
(1.2B) + B = 464
2.2B = 464
Divide each side by 2.2
B = 210.9, rounded to 211 (it's asking for days, not partial days, so round)
If Boston has 211 days of sunshine , then Colorado Springs has 1.2 times that amount. 211 * 1.2 = 253.2 (rounded to 253)
Verification
211 + 253 = 464

3 0

2 years ago

A psychologist obtains a random sample of 2020 mothers in the first trimester of their pregnancy. The mothers are asked to play

leva [86]

Answer:

First of all, we need to determine the system of hypothesis, which must have a null and alternative hypothesis.

In all hypothesis proof procedure, we must work with the null one, rejecting it or accepting it. If we reject the null hypothesis, it will mean that our principal hypothesis is true.

According to the problem, the null hypothesis must be: $H_{o} : u = 100$ ; because it says that 100 is the normal mean that is used.

The alternative hypothesis must be: $H_{a} : u > 100$ ; because the question is asking if there's enough evidence to say that they children have a higher IQ than 100.

Then, we must calculate the P-value, which is the probability value that we are gonna use to accept or reject the null hypothesis. This P-value we can calculate it with the formula: $Z=\frac{x-u}{\frac{o}{\sqrt{n} } }$ ; where x is the sample mean, u is the hypothetical mean parameter, o is the sample deviation and n is the sample.

Extracting all values from the problem: x = 104.3; u = 100; o = 14 and n = 20.

Applying all values to the formula: $Z=\frac{104.3 - 100}{\frac{14}{\sqrt{20} } } = \frac{4.3}{\frac{14}{ 4.5} }=\frac{4.3}{3.1}=1.4$

Then, this Z-value will give us the P-value by using the Z-table with the 0.05 level of significance. In table attached, we can see that the result is 0.9265. However, the P-value is 1 - 0.9265 = 0.735. We need to do this subtraction because, the result 0.9265 belong to the bigger area (as it's shown is the image in blue colour), and we need the smaller area, which belong to the 0.05 level of significance.

<em>In this problems, if the P-value is more than the level of significance, the null hypothesis is accepted. If the P-value is less than the level of significance the null hypothesis is rejected.</em>

Therefore, there is no enough evidence to say that the sample children have higher IQs, because the P-value is higher than the level of significance. (0.735>0.05).