All categories

3 years ago

Find 3 consecutive numbers where the product of the smaller two numbers is 19 less than the square of the largest number.

1 answer:

6 0

N; n+1; n+2 - 3 consecutive numbers

n(n + 1) = (n + 2)² - 19 |use a(b + c) = ab + ac and (a + b)² = a² + 2ab + b²

n² + n = n² + 4n + 4 - 19 |subtract n² from both sides

n = 4n - 15 |subtract 4n from both sides

-3n = -15 |divide both sides by (-3)

n = 5

n + 1 = 5 + 1 = 6

n + 2 = 5 + 2 = 7

Answer: 5; 6; 7.

You might be interested in

Lowest common multiple of 6 and 10

BigorU [14]

30 I think because 6 12 18 24 30 and 10 20 30

6 0

3 years ago

Read 2 more answers

what number, when added to the numerator and to the denominator of $\frac{5}{8}$, results in a fraction whose value is 0.4?

luda_lava [24]

The required number is -3 which when added to the numerator and to the denominator of 5/8 results in a fraction whose value is 0.4.

<h3>What is a fraction?</h3>

Fraction is the ratio of a particular part to the whole parts of an object. A fraction has a numerator and a denominator.

<h3>Calculation:</h3>

The given fraction is 5/8

Consider a number as 'x' which is added to both the numerator and the denominator of the given fraction.

So,

(5 + x)/(8 + x)

Since it is given that the result is 0.4 i.e., 4/10, we can write

(5 + x)/(8 + x) = 4/10

⇒ 10(5 + x) = 4(8 + x)

⇒ 50 + 10x = 32 + 4x

⇒ 10x - 4x = 32 - 50

⇒ 6x = -18

⇒ x = -18/6

∴ x = -3

Therefore, the required number is -3.

Check:

(5 + (-3))/(8 + (-3)) = (5 - 3)/(8 - 3) = 2/5 = 0.4

Learn more about fractions here:

brainly.com/question/17220365

#SPJ4

3 0

1 year ago

Let X represent the amount of gasoline (gallons) purchased by a randomly selected customer at a gas station. Suppose that the me

Alexus [3.1K]

Answer:

a) 18.94% probability that the sample mean amount purchased is at least 12 gallons

b) 81.06% probability that the total amount of gasoline purchased is at most 600 gallons.

c) The approximate value of the 95th percentile for the total amount purchased by 50 randomly selected customers is 621.5 gallons.

Step-by-step explanation:

To solve this question, we use the normal probability distribution and the central limit theorem.

Normal probability distribution

Problems of normally distributed samples are 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.

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 $s = \frac{\sigma}{\sqrt{n}}$ .

For a skewed variable, the Central Limit Theorem can also be applied, as long as n is at least 30.

For sums, we can apply the theorem, with mean $\mu$ and standard deviation $s = \sqrt{n}*\sigma$

In this problem, we have that:

$\mu = 11.5, \sigma = 4$

a. In a sample of 50 randomly selected customers, what is the approximate probability that the sample mean amount purchased is at least 12 gallons?

Here we have $n = 50, s = \frac{4}{\sqrt{50}} = 0.5657$

This probability is 1 subtracted by the pvalue of Z when X = 12.

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

By the Central Limit theorem

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

$Z = \frac{12 - 11.5}{0.5657}$

$Z = 0.88$

$Z = 0.88$ has a pvalue of 0.8106.

1 - 0.8106 = 0.1894

18.94% probability that the sample mean amount purchased is at least 12 gallons

b. In a sample of 50 randomly selected customers, what is the approximate probability that the total amount of gasoline purchased is at most 600 gallons.

For sums, so $mu = 50*11.5 = 575, s = \sqrt{50}*4 = 28.28$