Complete question :
The birthweight of newborn babies is Normally distributed with a mean of 3.96 kg and a standard deviation of 0.53 kg. Find the probability that an SRS of 36 babies will have an average birthweight of over 3.9 kg. Write your answer as a decimal. Round your answer to two places after the decimal
Answer:
0.75151
Step-by-step explanation:
Given that :
Mean weight (m) = 3.96kg
Standard deviation (σ) = 0.53kg
Sample size (n) = 36
Probability of average weight over 3.9
P(x > 3.9)
Using the z relation :
Zscore = (x - m) / (σ / √n)
Zscore = (3.9 - 3.96) / (0.53 / √36)
Zscore = - 0.06 / 0.0883333
Zscore = −0.679245
Using the Z probability calculator :
P(Z > - 0.679245) = 0.75151
= 0.75151
Basically, the parabola has to have all points that are equidistant from the focus and the directrix, the directrix being a horizontal line, and the focus being a point given. To derive an equation from this you need to use the distance formula which I'm guessing you already know because you're already in precalc.
The gist of it is that we have a random point on the parabola (x,y), and the point (x,y) will be equidistant from both the focus and the directrix. If we use the distance formula, you get something like this:

The square root of y-(-1/2) coming from the directrix, and the righthand side of the equal sign being derived from the focus.
All you need to do is simplify now!
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Hope I helped!
I hope this helps you out
Answer:
B- False
Step-by-step explanation:
Solve for n in 270=120 + n*10. 120 gives you first 30 minutes and n is the number of additional 10 minutes you ride. In this case you ride for 30+n*10 minutes. n = (270-120)/10 = 15. So the total time is 30+15*10 = 180 minutes. Or three hours!! That’s a lot of bumper cars!!