How do you decrease £840 by 5%

Mathematics

2 answers:

Advocard [28]4 years ago

7 0

£840 - 100%
100%-5%=95%
840*95%:100% = 798 (£) - <span>the number sought</span>

oee [108]4 years ago

4 0

To decrease by percentages you do 100 minus the percent you want to take away. In this case it's 100-5=95. Then divide 95 by 100 which is 0.95. This is the multiplier. Finally, times the multiplier by the number for your answer. In this situation it's 0.95*840=798. The answer is £798.

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Considering the number of questions incorrect from classmates on a quiz {10, 11, 12, 13, 13, 13, 14, 15, 16, 16, 17, 18, 18, 19,

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Answer:

According to the Empirical Rule, 68% of the data should fall between 11.98 and 18.02

Step-by-step explanation:

We are given the following data in the question:

10, 11, 12, 13, 13, 13, 14, 15, 16, 16, 17, 18, 18, 19, 20

Formula:

$\text{Standard Deviation} = \sqrt{\displaystyle\frac{\sum (x_i -\bar{x})^2}{n-1}}$

where $x_i$ are data points, $\bar{x}$ is the mean and n is the number of observations.

$Mean = \displaystyle\frac{\text{Sum of all observations}}{\text{Total number of observation}}$

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Empirical rule:

According to this rule almost all the data lies within three standard deviation of the mean for a normal distribution.
About 68% of data lies within one standard deviation of the mean.
About 95% of data lies within two standard deviations of mean.
Arround 99.7% of data lies within three standard deviation of mean.

Thus, by empirical rule,

$\mu \pm 1\sigma = 15\pm (3.02) = (11.98,18.02)$