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vova2212 [387]
3 years ago
14

Two lengths are in the ratio 2:5. The second length is 75 cm. Find the first length.​

Mathematics
1 answer:
vichka [17]3 years ago
7 0

Answer:

30 cm

Step-by-step explanation:

2 * 15: 5 * 15

    30:75

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How many real solutions are there for f(x) = (x + 3)^2 – 8?
Molodets [167]
There are 2 solutions. the highest degree of a polynomial is 2
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3 years ago
There are 75 boys in the sixth grade. The ratio of girls to boys is 7 to 5. How many girls are there in sixth grade?
kolbaska11 [484]
There are 105 in 6th grade because there are 75 boys right? So it said the ratio of girls is 7 and the ratio of boys is 5 so I divided 75 to 5 = 15 and I multiply 7 to 15 and got 105 girls.
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4 years ago
. Explain why projectile motion, such as kicking a ball off the top of building, has a curved path. Identify the two forces invo
deff fn [24]

The initial kick is the first force applied to the ball. It sends the ball up into the air (at some angle). If gravity wasn't present, then the ball would go upward forever in a straight line. However, gravity is the second force pulling down on the ball. This explains why the ball hits some peak point or highest point before it is pulled to the ground. Overall, the path the ball takes is a parabolic arch.

In short, the two forces are the initial kick and gravity.

side note: technically air resistance (aka air friction or drag) is a force being applied since the air pushes against the ball to slow it down, but often air resistance is really complicated and beyond the scope of many math courses. So your teacher may want you to ignore air resistance.

Another note: the initial kick is a one time force that only happens at the beginning. Once the ball is in the air, that force isn't applied anymore. In contrast, the force of gravity is always present and always pulling down. It's probably incredibly obvious, but it's worth pointing out this difference.

4 0
4 years ago
A​ 9-year-old girl did a science fair experiment in which she tested professional touch therapists to see if they could sense he
Orlov [11]

Answer:

We conclude that the the touch therapists does not use a method equivalent to random guesses.

Yes, the results suggest that touch therapists are​ effective.

Step-by-step explanation:

We are given that in a 9-year-old girl did a science fair experiment in which she tested professional touch therapists to see if they could sense her energy field.

Among 264264 ​trials, the touch therapists were correct 105105 times.

<u><em>Let p = proportion that touch therapists uses a random guess method.</em></u>

Here, random guess means; p = 50%

So, Null Hypothesis, H_0 : p = 50%     {means that the touch therapists use a method equivalent to random guesses}

Alternate Hypothesis, H_A : p \neq 50%     {means that the touch therapists does not use a method equivalent to random guesses}

The test statistics that would be used here <u>One-sample z proportion statistics</u>;

                         T.S. =  \frac{\hat p-p}{\sqrt{\frac{\hat p(1-\hat p)}{n} } }  ~ N(0,1)

where, \hat p  = sample proportion of touch therapists were correct = \frac{105}{264} = 0.39

            n = sample of trials = 264

So, <em><u>test statistics</u></em>  =  \frac{\frac{105}{264} -0.50}{\sqrt{\frac{\frac{105}{264}(1-\frac{105}{264})}{264} } }  

                                =  -3.395

The value of z test statistics is -3.395.

<em>Now, at 0.05 significance level the z table gives critical value of -1.96 and 1.96 for two-tailed test. Since our test statistics does not lie within the range of critical values of z, so we have sufficient evidence to reject our null hypothesis as it will in the rejection region due to which </em><u><em>we reject our null hypothesis</em></u><em>.</em>

Therefore, we conclude that the the touch therapists does not use a method equivalent to random guesses.

Yes, the results suggest that touch therapists are​ effective.

3 0
3 years ago
Please help!!<br>fully simplify<br><br><img src="https://tex.z-dn.net/?f=%5Cfrac%7B%5Csqrt%7B300%7D%2B%5Csqrt%7B27%7D-%5Csqrt%7B
bija089 [108]

Answer:

The answer is 2

Step-by-step explanation:

Multiply the numerator and denominator by the conjugate.

6 0
3 years ago
Read 2 more answers
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