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3 years ago

5(n - 7) = 2 (n + 14)

Mathematics

1 answer:

m_a_m_a [10]3 years ago

4 0

Answer n=21
5n-35=2n+28

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Set A of six numbers has a standard deviation of 3 and set B of four numbers has a standard deviation of 5. Both sets of numbers

Alenkinab [10]

Given:

$\sigma_A=3$

$n_A=6$

$\sigma_B=5$

$n_B=4$

$\overline{x}_A=\overline{x}_B$

To find:

The variance. of combined set.

Solution:

Formula for variance is

$\sigma^2=\dfrac{\sum (x_i-\overline{x})^2}{n}$ ...(i)

Using (i), we get

$\sigma_A^2=\dfrac{\sum (x_i-\overline{x}_A)^2}{n_A}$

$(3)^2=\dfrac{\sum (x_i-\overline{x}_A)^2}{6}$

$9=\dfrac{\sum (x_i-\overline{x}_A)^2}{6}$

$54=\sum (x_i-\overline{x}_A)^2$

Similarly,

$\sigma_B^2=\dfrac{\sum (x_i-\overline{x}_B)^2}{n_B}$

$(5)^2=\dfrac{\sum (x_i-\overline{x}_B)^2}{4}$

$25=\dfrac{\sum (x_i-\overline{x}_B)^2}{4}$

$100=\sum (x_i-\overline{x}_B)^2$

Now, after combining both sets, we get

$\sigma^2=\dfrac{\sum (x_i-\overline{x}_A)^2+\sum (x_i-\overline{x}_B)^2}{n_A+n_B}$

$\sigma^2=\dfrac{54+100}{6+4}$

$\sigma^2=\dfrac{154}{10}$

$\sigma^2=15.4$

Therefore, the variance of combined set is 15.4.

7 0

2 years ago

2 plus 2 and 45 plus 68

natulia [17]

Answer:

117

Step-by-step explanation:

8 0

2 years ago

Read 2 more answers

A fair spinner has eight equal sections.

blagie [28]

Answer:

umm im not sure if its correct but do 2 ( the colors ) times how many times it is spun. so there are 6 .

Step-by-step explanation:

4 0

2 years ago

Read 2 more answers

Aaron has three slabs of beeswax. He plans to melt them and use all of the wax to form 36 candles. If all the candles are the sa

Anton [14]

Weight of slab of beeswax isn't given.

Assume slab of beeswax = 36 gram.

Answer:

3 gram

Step-by-step explanation:

Each slab of beeswax = 36 gram

Total weight of all 3 slabs = (3 * 36) = 108 g

Number of same-sized candles to make = 36

The weight of each candle will be ;

Total weight of slabs / number of candles

108 g / 36

= 3 grams

8 0

3 years ago

A recipe calls for blueberry muffins cost for 2 3/4 cup of blueberries. You are making 1/3 of the recipe. How much blueberries s

tester [92]

Answer: 8/9 cups

Step-by-step explanation:

The word 'of' means 'times' as far as fractions are concerned. In this case, we have 1/3 of 2 1/3.

First, it is a good idea to make 2 1/3 an improper fraction - as 8/3, so now we have:

1/3 of 8/3, but since 'of' means 'times' we have,

1/3 x 8/3 = 8/9

The answer is 8/9 cups.

7 0

2 years ago