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3 years ago

What is the perimeter of a rectangle whose width is (x - 7) units and whose length is (3x + 10) units?

Mathematics

1 answer:

FromTheMoon [43]3 years ago

4 0

Answer:

The answer is "(8x + 6) units".

Step-by-step explanation:

Formula of perimeter is:

$\to \bold{P=2 \text{(Length +width)} }$

$=2((3x+10)+(x-7))\\\\=2(4x+3)\\\\= 8x+6$

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Alana ate breakfast at a restaurant. The bill came to $79.75. If she left 20% tip, how much was the tip?

Lana71 [14]

$79.75*0.2= 15.95
$79.75-15.95= $63.80
63.80+15.95= $79.75

Answer= $15.95

3 0

3 years ago

Select the two binomials that are factors of this trinomial.

Stella [2.4K]

we are given

trinomial as

$x^2 -x -12$

now, we can factor it

$x^2 -x -12= x^2 -4x +3x -4*3$

$x^2 -x -12= x(x -4) +3(x -4)$

$x^2 -x -12= (x-4)(x+3)$

so, option-C and D ..............Answer

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4 years ago

Surface area of solid cuboid 8cm 6cm 2cm

strojnjashka [21]

Answer:

152 $\text{cm}^2$

Step-by-step explanation:

We know that the total surface area of a cuboid is the sum of the surface area of all six of its faces.

We also know that each opposing side has the same surface area. Thus the total surface area is equal to:

$2*(8*6+8*2+6*2)\\\\=2*(48+16+12)\\=2*76\\=152$ ( $\text{cm}^2$ )

6 0

2 years ago

A researcher reports survey results by stating that the standard error of the mean is 25 the population standard deviation is 40

bezimeni [28]

Answer:

a) A sample of 256 was used in this survey.

b) 45.14% probability that the point estimate was within ±15 of the population mean

Step-by-step explanation:

This question is solved using the normal probability distribution and the central limit theorem.

Normal probability distribution

When the distribution is normal, we use 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.

Central Limit Theorem

The Central Limit Theorem estabilishes that, for a normally distributed random variable X, with mean $\mu$ and standard deviation $\sigma$ , the sampling distribution of the sample means with size n can be approximated to a normal distribution with mean $\mu$ and standard deviation $s = \frac{\sigma}{\sqrt{n}}$ .