All categories

3 years ago

Please someone help me with this I am very confused

Mathematics

1 answer:

Elis [28]3 years ago

4 0

$8 \sqrt{3} *4 \sqrt{15} = 8*4 \sqrt{3*15} \\ \\ 32 \sqrt{45} = 32 \sqrt{9*5} =32*3 \sqrt{5} \\ \\ = 96 \sqrt{5} 
$

You might be interested in

Standard notation 8.15×10^5

sukhopar [10]

Answer:

8.15×10^5

Step-by-step explanation:

8.15×10^5

8.15×100000

815000

8 0

3 years ago

Area of a trapezium is 31.5cm. If the parallel sides are of lengths 7.3cm and 5.3cm. Calculate the perpendicular distance betwee

Anna11 [10]

Answer:

5cm

Step-by-step explanation:

Given area of trapezium = 31.5 sq. cm

Length of parallel sides = 7.3cm and 5.3cm

Formula to calculate area of trapezium is

1/2*(sum of parallel sides)*perpendicular distance between parallel sides

sum of parallel sides = (7.3 + 5.3) = 12.6cm

substituting value of area given and sum of parallel sides we have

31.5 = 1/2* 12.6 * perpendicular distance between parallel sides

(31.5 * 2)/12.6 = perpendicular distance between parallel sides

perpendicular distance between parallel sides = 63/12.6 = 5

Therefore perpendicular distance between parallel sides for given trapezium is 5cm.

5 0

3 years ago

A recent survey based on a random sample of n=470 voters, predicted that independent candidate for the mayoral election will get

julsineya [31]

I have an expression

$\sigma = \sqrt{p(1-p)/n}$

floating around in my head; let's see if it makes sense.

The variance of binary valued random variable b that comes up 1 with probability p (so has mean p) is

$E( (b-p)^2 ) = (-p)^2(1-p) + (1-p)^2p = p(1-p)$

That's for an individual sample. For the observed average we divide by n, and for the standard deviation we take the square root:

$\sigma = \sqrt{p(1-p)/n}$

Plugging in the numbers,

$\sigma = \sqrt{.24(1-.24)/490} = 0.019 = 1.9\%$

One standard deviation of the average is almost 2% so a 27% outcome was 3/1.9 = 1.6 standard deviations from the mean, corresponding to a two sided probability of a bit bigger than 10% of happening by chance.

So this is borderline suspect; most surveys will include a two sigma margin of error, say plus or minus 4 percent here, and the results were within those bounds.

7 0

3 years ago

What are two ratios that are equivalent to 4:6

Alecsey [184]

Answer:

8:12,16:24,32:48,20:30

3 0

3 years ago

A flashlight battery manufacturer makes a model of battery whose mean shelf life is three years and four months, with a standard

Vladimir [108]

Answer:

17,065 of those batteries can be expected to last between three years and one month and three years and seven months

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:

I will calculate the time in months. Each year has twelve months.

Mean shelf life is three years and four months, with a standard deviation of three months. So

$\mu = 3*12 + 4 = 40$