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uysha [10]
3 years ago
6

Two bicyclists are 7/8 of the way through a mile long tunnel when a train approaches the closer end at 40 mph. The riders take o

ff at the same speed in opposite directions and each escapes the tunnel as the train passes them. How fast did they ride?
Mathematics
1 answer:
Anastaziya [24]3 years ago
6 0

Answer:

the cyclists rode at 35 mph

Step-by-step explanation:

Assuming that the cyclists stopped, and accelerated instantaneously at the same speed than before but in opposite direction , then

distance= speed*time

since the cyclists and the train reaches the end of the tunnel at the same time and denoting L as the length of the tunnel :

time = distance covered by cyclists / speed of cyclists = distance covered by train / speed of the train

thus denoting v as the speed of the cyclists :

7/8*L / v = L / 40 mph

v = 7/8 * 40 mph = 35 mph

v= 35 mph

thus the cyclists rode at 35 mph

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Anyone please help!!!
Tanya [424]

Problem 1

Answers:

Percentage of patients that were dogs = 46%

Standard Error = 0.07048404074682

Margin of error for 90% confidence interval = 0.11594624702851

Margin of error for 95% confidence interval = 0.13814871986377

Round the decimal values however you need them

------------

To get the first answer, you add up the numbers given (7,4,5,5,2) and divide that over 50. So 7+4+5+5+2 = 23 which leads to 23/50 = 0.46 = 46%; therefore phat = 0.46 is the sample proportion of dogs.

Use the SE (standard error) formula given to you with phat = 0.46 and n = 50 to get SE = 0.07048404074682

The critical z value at 90% confidence is 1.645; this value is found in your Z table (back of your stats textbook). Multiply the SE value by 1.645 to get 0.07048404074682*1.645 = 0.11594624702851

Also found in your textbook is 1.960 which is the z critical value at 95% confidence. Multiply this with the SE value to get 0.07048404074682*1.960 = 0.13814871986377

===============================================

Problem 2

Answer: Choice B) picking balls from a bin; the 60 randomly selected get chosen for the first bus, while the remaining 60 go to the second bus

-----------

Choice A is fairly vague on what the lower and upper boundaries are. What is the smallest number allowed? What about the largest? This isn't clear so it's possible that we could end up with more positive numbers than negative (eg: if we had an interval -10 < x < 110). So choice A is false. A similar issue shows up with choice D.

Choice B is true. Assuming the selection process is random and not biased, then each ball is equally likely for each selection. The fact that the balls are colored seems to be extra info which I'm not sure why your teacher threw that in there.

Choice C is false because choice B is true

Choice D is false for similar reasons as choice A. It's not clear where we start and where we end. If we had the interval 2 < x < 6 then x could take on the values {3, 4, 5} and we see that picking an odd number is twice as likely than picking an even. In this example, there is bias.

===============================================

Problem 3

Answer: Choice B) Roll a die; each number corresponds to a different class

------------

Choice A is false because choice B being the answer contradicts it

Choice B is true: there are 6 sides on the die, and each side is equally likely to be landed on, so each class is equally likely

Choice C is false because 2*2*2 = 8 represents the number of combos you can have when you flip three coins (one combo being HTH for heads tail heads) but there are 6 classes, not 8

Choice D is false because while we want 6 regions on the spinner. Each region must have the same area; otherwise, one class is weighted heavier than the others making it more likely you select that particular class.


7 0
3 years ago
Read 2 more answers
Write the equation for the perpendicular bisector of a segment that has endpoints (–1, 10) and (3, 6).
BaLLatris [955]

Answer: I believe it’s y=x+7

Step-by-step explanation:

7 0
3 years ago
Please solve for me and give me a caculator where i can find out how to do this
tekilochka [14]
We can help you and somebody can help you with calculator
4 0
3 years ago
What number is ten thousand less than 842,719
Arte-miy333 [17]


The answer is 832,719.

842,719  - 10,000 = 832,719

6 0
3 years ago
B: Alex is 12 years older than George.
UkoKoshka [18]

Answer:

The ratio of George age to Carl's age is 1:12.

Step-by-step explanation:

Let the age of George be 'g'.

Let the age of Alex be 'a'.

Also Let the age of Carl be 'c'.

Given:

The sum of their ages is 68.

So equation can be framed as;

g+a+c=68 \ \ \ \ equation 1

Also Given:

Alex is 12 years older than George.

So equation can be framed as;

a =g+12 \ \ \ \ equation \ 2

Now Given:

Carl is three times older than Alex.

c=3a

But a =g+12

So we get;

c = 3(g+12) \\\\c= 3g+36 \ \ \ \ equation \ 3

Now Substituting equation 2 and equation 3 in equation 1 we get;

g+a+c=68\\\\g+g+12+3g+36=68\\\\5g+48=68

Subtracting both side by 48 using subtraction property of equality we get;

5g+48-48=68-48\\\\5g=20

Now Dividing both side by 5 using Division property of equality we get;

\frac{5g}{5}=\frac{20}{5}\\\\g =4

Hence George age g = 4 \ years

Now Alex age a=g+12 = 4+12 =16\ years

Also Carl's age c=3g+36=3\times 4+36 =12+36 =48\ years

Now we need to find the ratio of George age to Carl's age.

\frac{g}{c}=\frac{4}{48} = \frac{1}{12}

Hence  the ratio of George age to Carl's age is 1:12.

3 0
3 years ago
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