There is no common factor between 15, 17 and 18 because 17 is prime.
15z² +17z - 18 =
d = 17² - 4.15.-18
d = 289 + 1080
d = 1369
z = (-17 +/- \/1369) : 2 * 15
z = (-17 + 37) : 30
z' = 20 : 30 = 2/3
z" = (-17 - 37) : 30
z" = -54 : 30 = -1.8
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Answer:
20 fish.
Step-by-step explanation:
Convert ratio to fraction:
There were 5 / (5 + 2) = 5/7 of fish.
So number of fish = 5/7 * 28
= 20.
Answer:
I guess I could be ur friend
Answer: Prokhorova is more outstanding.
Step-by-step explanation: To compare scores from different distributions, first standardize it:
z-score = 
where
x is the individual mean you want to compare
μ is the mean of the population
σ is standard deviation
For <u>Gertrud Bacher</u>:
z-score = 
z-score =
(s)
The negative sign indicates Bacher's mean is less than the mean
For <u>Yelena Prokhorova</u>:
z-score = 
z-score = 2 (cm)
The positive sign indicates Prokhorova's mean is more than the mean.
Using z-score table, you determine the percentiles are:
For Bacher: Percentile = 5.5%
For Prokhorova: Percentile = 97.7%
Bacher's percentile means she is above 5.5% of the participants, while Prokhorova is 97.7% above the other competitors, which means Prokhorova have a better performance and deserves more points.