I am so confused... please help!

Mathematics

1 answer:

nydimaria [60]2 years ago

5 0

Answer:

Step-by-step explanation:

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If a+b=9 and ab=18,find the value of a and b.

Blizzard [7]

Answer:

Given:

a + b = 9

=> a = 9 - b

Given:

a x b = 18

=> (9 - b) x b = 18

=> 9b - b^2 = 18

=> b^2 - 9b + 18 = 0

=> (b - 3)(b - 6) = 0

=> b = 3 => a = 6

=> b = 6 => a = 3

Hope this helps

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3 years ago

4.1 Unit Rates

fiasKO [112]

Answer: 17.5

Step-by-step explanation:

8 0

2 years ago

The following data gives the speeds (in mph), as measured by radar, of 10 cars traveling north on I-15. 76 72 80 68 76 74 71 78

____ [38]

Answer:

71.123 mph ≤ μ ≤ 77.277 mph

Step-by-step explanation:

Taking into account that the speed of all cars traveling on this highway have a normal distribution and we can only know the mean and the standard deviation of the sample, the confidence interval for the mean is calculated as:

$m-t_{a/2,n-1}\frac{s}{\sqrt{n} }$ ≤ μ ≤ $m+t_{a/2,n-1}\frac{s}{\sqrt{n} }$

Where m is the mean of the sample, s is the standard deviation of the sample, n is the size of the sample, μ is the mean speed of all cars, and $t_{a/2,n-1}$ is the number for t-student distribution where a/2 is the amount of area in one tail and n-1 are the degrees of freedom.

the mean and the standard deviation of the sample are equal to 74.2 and 5.3083 respectively, the size of the sample is 10, the distribution t- student has 9 degrees of freedom and the value of a is 10%.

So, if we replace m by 74.2, s by 5.3083, n by 10 and $t_{0.05,9}$ by 1.8331, we get that the 90% confidence interval for the mean speed is: