NEED HELP ASAP PLEASE

Help someone I just need the answer

ehidna [41]

There is no question

4 0

3 years ago

Simplify the expression. (5x2 - x - 7) + (2x2 + 3x + 4)

kifflom [539]

Answer:11+2x

Step-by-step explanation:

(10-7-x)+(4+4+3x)

3-x+8+3x

3+8+3x-x

11+2x

3 0

3 years ago

(1/2)/(2/3) evaluate

nikitadnepr [17]

Answer:

$\frac{3}{4}$

Step-by-step explanation:

Find a common denominator for the 2 denominators: 6
Change the fractions: 2 × 3 = 6, 1 × 3 = 3, 3 × 2 = 6, 2 × 2 = 4
Re-write the fractions: $\frac{3}{6}$ and $\frac{4}{6}$
Write as an expression: $\frac{3}{6}$ ÷ $\frac{4}{6}$
$\frac{3}{6}$ ÷ $\frac{4}{6}$ = $\frac{3}{6}$ × $\frac{6}{4}$
$\frac{3}{6}$ × $\frac{6}{4} = \frac{18}{24}$
$\frac{18}{24} = \frac{3}{4}$

I hope this helps!

8 0

2 years ago

In a certain country, approximately 22 out of 100 people over the age of 12 smoke. How many smokers would you expect in a group

Elan Coil [88]

Answer:

121 smokers

Step-by-step explanation:

This can be calculated as a simple rule of 3.

In these problems, the first step is identifying the measures in the problem. Then, we must identify whether their relation is direct or inverse.

When it is direct, as one measure increases, the other will increase too.

When it is inverse, as one measure increases, the other will decrease.

In this problem, the measures are the number of people over 12 that smoke, and the total number of people over 12. Their relation is direct, because as the number of people increases, the number of smokers will increase too.

So we must solve the following rule of three:

22 smokers - 100 people

x smokers - 550 people

x = 550*22/100

x = 22*5.5

x = 121 smokers.

So, in a group off 550 people over the age of 12, there are 121 expected smokers.

8 0

3 years ago

The level of nitrogen oxides (NOX) in a exhaust of cars of a particular model varies normally with mean 0.25 grams per miles and

antoniya [11.8K]

Answer:

a) 15.87% probability that a single car of this model fails to meet the NOX requirement.

b) 2.28% probability that the average NOX level of these cars are above 0.3 g/mi limit

Step-by-step explanation:

We use the normal probability distribution and the central limit theorem to solve this question.

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 random variable X, with mean $\mu$ and standard deviation $\sigma$ , a large sample size can be approximated to a normal distribution with mean $\mu$ and standard deviation $s = \frac{\sigma}{\sqrt{n}}$