Help please with this math

Help I need answers

natali 33 [55]

We can easily work out the meter reading in October. It comes out to be 32347 + 972. So the reading in October must be around 33319.

SO the answer to second question is really easy to figure out too. As we know that one unit costs 14 p we can simply multiply the cost with the number of units consumed.

So for 972 units if we multiply by 14 we get the cost to be around somewhere 13608 p.

6 0

2 years ago

A certain radioactive isotope has a half-life of 15 days. If one is to make a table showing the half-life decay of a sample of t

Verdich [7]

A half-life of the isotope is 15 days and at start its mass is 32 g.
A table:
t: m:
0 32 g
15 16 g
30 8 g
45 4 g
60 2 g
75 1 g
In the first column is used an arithmetic sequence ( a 1 = 0, d = 15 ).
In the second column is used a geometric sequence ( a 1 = 32, r = 1/2 )

7 0

3 years ago

Life Expectancies In a study of the life expectancy of people in a certain geographic region, the mean age at death was years an

Sphinxa [80]

Answer:

The probability that the mean life expectancy of the sample is less than X years is the p-value of $Z = \frac{X - \mu}{\frac{\sigma}{\sqrt{n}}}$ , in which $\mu$ is the mean life expectancy, $\sigma$ is the standard deviation and n is the size of the sample.

Step-by-step explanation:

To solve this question, we need to understand the normal probability distribution and the central limit theorem.

Normal Probability Distribution

Problems of normal distributions can be solved using the z-score formula.

In a set with mean $\mu$ and standard deviation $\sigma$ , the z-score 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 p-value, we get the probability that the value of the measure is greater than X.

Central Limit Theorem

The Central Limit Theorem establishes 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.

We have:

Mean $\mu$ , standard deviation $\sigma$ .

Sample of size n:

This means that the z-score is now, by the Central Limit Theorem:

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

Find the probability that the mean life expectancy will be less than years.

The probability that the mean life expectancy of the sample is less than X years is the p-value of $Z = \frac{X - \mu}{\frac{\sigma}{\sqrt{n}}}$ , in which $\mu$ is the mean life expectancy, $\sigma$ is the standard deviation and n is the size of the sample.

8 0

2 years ago

What is the estimate of the sum of 6/10 + 7/12

aleksandr82 [10.1K]

71/60. You change the denominators(bottom numbers) to 60 because that is the smallest number that both 10 and 12 can go into. Then you just add.

8 0

3 years ago

Evaluate g(3) if g(x) = 2x + 1. 0 1 07 24

evablogger [386]

Answer:

g(3) = 7

Step-by-step explanation:

g(3) means to substitute "x" for 3.

Change any "x" in the function to 3. Then solve.

Take the function

g(x) = 2x + 1

Substitute x = 3

g(3) = 2(3) + 1

Solve with BEDMAS order (brackets, exponents, division, multiplication, addition, subtraction).

g(3) = 2(3) + 1 Multiply first

g(3) = 6 + 1 Add

g(3) = 7 Answer

5 0

3 years ago