Answer:
The lifeguard should run across the shore a distance of 48.074 m before jumpng into the water in order to minimize the time to reach the child.
Step-by-step explanation:
This is a problem of optimization.
We have to minimize the time it takes for the lifeguard to reach the child.
The time can be calculated by dividing the distance by the speed for each section.
The distance in the shore and in the water depends on when the lifeguard gets in the water. We use the variable x to model this, as seen in the picture attached.
Then, the distance in the shore is d_b=x and the distance swimming can be calculated using the Pithagorean theorem:
Then, the time (speed divided by distance) is:
To optimize this function we have to derive and equal to zero:
![\dfrac{dt}{dx}=\dfrac{1}{4}+\dfrac{1}{1.1}(\dfrac{1}{2})\dfrac{2x-120}{\sqrt{x^2-120x+5200}} \\\\\\\dfrac{dt}{dx}=\dfrac{1}{4} +\dfrac{1}{1.1} \dfrac{x-60}{\sqrt{x^2-120x+5200}} =0\\\\\\ \dfrac{x-60}{\sqrt{x^2-120x+5200}} =\dfrac{1.1}{4}=\dfrac{2}{7}\\\\\\ x-60=\dfrac{2}{7}\sqrt{x^2-120x+5200}\\\\\\(x-60)^2=\dfrac{2^2}{7^2}(x^2-120x+5200)\\\\\\(x-60)^2=\dfrac{4}{49}[(x-60)^2+40^2]\\\\\\(1-4/49)(x-60)^2=4*40^2/49=6400/49\\\\(45/49)(x-60)^2=6400/49\\\\45(x-60)^2=6400\\\\](https://tex.z-dn.net/?f=%5Cdfrac%7Bdt%7D%7Bdx%7D%3D%5Cdfrac%7B1%7D%7B4%7D%2B%5Cdfrac%7B1%7D%7B1.1%7D%28%5Cdfrac%7B1%7D%7B2%7D%29%5Cdfrac%7B2x-120%7D%7B%5Csqrt%7Bx%5E2-120x%2B5200%7D%7D%20%5C%5C%5C%5C%5C%5C%5Cdfrac%7Bdt%7D%7Bdx%7D%3D%5Cdfrac%7B1%7D%7B4%7D%20%2B%5Cdfrac%7B1%7D%7B1.1%7D%20%5Cdfrac%7Bx-60%7D%7B%5Csqrt%7Bx%5E2-120x%2B5200%7D%7D%20%3D0%5C%5C%5C%5C%5C%5C%20%20%5Cdfrac%7Bx-60%7D%7B%5Csqrt%7Bx%5E2-120x%2B5200%7D%7D%20%3D%5Cdfrac%7B1.1%7D%7B4%7D%3D%5Cdfrac%7B2%7D%7B7%7D%5C%5C%5C%5C%5C%5C%20x-60%3D%5Cdfrac%7B2%7D%7B7%7D%5Csqrt%7Bx%5E2-120x%2B5200%7D%5C%5C%5C%5C%5C%5C%28x-60%29%5E2%3D%5Cdfrac%7B2%5E2%7D%7B7%5E2%7D%28x%5E2-120x%2B5200%29%5C%5C%5C%5C%5C%5C%28x-60%29%5E2%3D%5Cdfrac%7B4%7D%7B49%7D%5B%28x-60%29%5E2%2B40%5E2%5D%5C%5C%5C%5C%5C%5C%281-4%2F49%29%28x-60%29%5E2%3D4%2A40%5E2%2F49%3D6400%2F49%5C%5C%5C%5C%2845%2F49%29%28x-60%29%5E2%3D6400%2F49%5C%5C%5C%5C45%28x-60%29%5E2%3D6400%5C%5C%5C%5C)
As 
, the lifeguard should run across the shore a distance of 48.074 m before jumpng into the water in order to minimize the time to reach the child.
Using the probability concept, it is found that there is a 0.7361 = 73.61% probability that the senior selected will not be from high school b given that the senior responded with a choice other than college.
<h3>What is a probability?
</h3>
- A <em>probability </em>is given by the <u>number of desired outcomes divided by the number of total outcomes</u>.
Researching the problem on the internet, it is found that:
- 538 seniors responded with a choice other than college.
- Of those students, 99 + 83 + 49 + 31 + 63 + 71 = 396 are not from high school b.
Hence:
0.7361 = 73.61% probability that the senior selected will not be from high school b given that the senior responded with a choice other than college.
You can learn more about the probability concept at brainly.com/question/26148436
Answer:
a
The estimate is 
b
Method B this is because the faulty breaks are less
Step-by-step explanation:
The number of microchips broken in method A is 
The number of faulty breaks of method A is 
The number of microchips broken in method B is 
The number of faulty breaks of method A is 
The proportion of the faulty breaks to the total breaks in method A is
The proportion of the faulty to the total breaks in method B is
For this estimation the standard error is
substituting values
The z-values of confidence coefficient of 0.95 from the z-table is
The difference between proportions of improperly broken microchips for the two breaking methods is mathematically represented as
![K = [p_1 - p_2 ] \pm z_{0.95} * SE](https://tex.z-dn.net/?f=K%20%3D%20%5Bp_1%20-%20p_2%20%5D%20%5Cpm%20z_%7B0.95%7D%20%2A%20SE)
substituting values
![K = [0.08 - 0.07 ] \pm 1.96 *0.0186](https://tex.z-dn.net/?f=K%20%3D%20%5B0.08%20-%200.07%20%5D%20%5Cpm%201.96%20%2A0.0186)
The interval of the difference between proportions of improperly broken microchips for the two breaking methods is
Answer:
90°.
Step-by-step explanation:
if AR is diameter and the angle ∠AOR (it's m∠2) is based on this diameter, then its measure is 90°. It is central angle.
Answer:
not sure i hope you find someone to help u tho soon
Step-by-step explanation:
