Use mental math to evaluate the expression 6(31)+6(4)-6(15)

Mathematics

2 answers:

Nana76 [90]3 years ago

7 0

Okay this is how i did it,

6(31) + 6(4) - 6(15)
186 + 24 - 90
= 120

Finger [1]3 years ago

3 0

Remember distributive property
a(b+c)=ab+ac
we can ervers it

6(31)+6(4)-6(15)=6(31)+6(4)+6(-15)=6(31+4-15)=6(20)=120

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Answer:

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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:

The mean ROE for the firms studied was 14.93% and the standard deviation was 21.74%. This means that $\mu = 0.1493, \sigma = 0.2174$

What value of ROE will be exceeded by 78% of the firms?

This is the value of X when Z has a pvalue of 1-0.78 = 0.22.

This is $Z = -0.77$

So:

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

$-0.77 = \frac{X - 0.1493}{0.2174}$

$X - 0.1493 = -0.77*0.2174$

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Answer:

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Step-by-step explanation:

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