Michael is 3 times as old as Brandon. 18 years ago, Michael was 9 times as old as Brandon.

1 answer:

5 0

I hope this helps you

Brandon x

Michael 3x

18 years ago

Brandon x-18

Michael 3x-18

9 (x-18)=3x-18

9x-9.18=3x-18

9x-3x=9.18-18

6x=8.18

x=8.3

x= 24

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irinina [24]

Answer: im thinking it is 5 but i could be totally wrong. im not the smartest lol

Step-by-step explanation:

6 0

3 years ago

In a recent contest, the mean score was 210 and the standard deviation was 25. a) Find the z-score of John who scored 190 b) Fin

denpristay [2]

Answer:

a) $Z = -0.8$

b) $Z = 2.4$

c) Mary's score was 241.25.

Step-by-step explanation:

Problems of normally distributed samples can be solved using the z-score formula.

In a set with mean $\mu$ and standard deviation $\sigma$ , the zscore of a measure X is given by:

$Z = \frac{X - \mu}{\sigma}$

The Z-score measures how many standard deviations the measure is from the mean. After finding the Z-score, we look at the z-score table and find the p-value associated with this z-score. This p-value is the probability that the value of the measure is smaller than X, that is, the percentile of X. Subtracting 1 by the pvalue, we get the probability that the value of the measure is greater than X.

In this problem, we have that:

$\mu = 210, \sigma = 25$