All categories

3 years ago

Need help with 3 and 4

Mathematics

2 answers:

Rufina [12.5K]3 years ago

6 0

Answer:
3) 9.2ml
4) .25ml

Have to have 20 characters

Oliga [24]3 years ago

5 0

Answer:

3. 9.2 mL; 4. 0.25 mL

Step-by-step explanation:

3. 12 mL syringe

The arrow points to the first division between 9 mL and 10 mL.

There are five divisions, so

5 divisions = 1.0 mL or

1 division = 0.2 mL

The reading is

9.0 mL + 0.2 mL = 9.2 mL

4. 0.5 mL syringe

The arrow points to the fifth division between 0.20 mL and 0.30 mL.

There are 10 divisions, so

10 divisions = 0.10 mL or

1 division = 0.01 mL

5 divisions = 0.05 mL

The reading is

0.20 mL + 0.05 mL = 0.25 mL

You might be interested in

Suppose there are 21 students in your class. If the teacher draws 2 names at random, what is the probability that you and your b

natali 33 [55]

1/21 * 1/20 = 1/420 that is the probability that you are chosen first.
Probability of your friend chosen first = 1/420 also.

So the required probability = 1/420 + 1/420 = 1/210 Answer

Its D

7 0

3 years ago

Construct a 95% confidence interval for the population mean, mu. Assume the population has a normal distribution. A random sam

aniked [119]

Given Information:

Number of lithium batteries = n = 16

Mean life of lithium batteries = μ = 645 hours

Standard deviation of lithium batteries = σ = 31 hours

Confidence level = 95%

Required Information:

Confidence Interval = ?

Answer:

$CI = 628.5 \: to \: 661.5 \: hours$

Step-by-step explanation:

The confidence interval is given by

$CI = \mu \pm t_{\alpha/2} (\frac{\sigma}{\sqrt{n}})$

Where μ is the mean life of lithium batteries, σ is the standard deviation, n is number of lithium batteries selected, and t is the critical value from the t-table with significance level of

tα/2 = (1 - 0.95) = 0.05/2 = 0.025

and the degree of freedom is

DoF = n - 1 = 16 - 1 = 15

The critical value (tα/2) at 15 DoF is equal to 2.131 (from the t-table)

$CI = 645 \pm 2.131(\frac{31}{\sqrt{16}})$

$CI = 645 \pm 2.131(7.75})$

$CI = 645 \pm 16.515$

$CI = 645 - 16.515 \: and \: 645 + 16.515$

$CI = 628.5 \: to \: 661.5 \: hours$

Therefore, the 95% confidence interval is 628.5 to 661.5 hours

What does it mean?

It means that we are 95% confident that the mean life of 16 lithium batteries is within the interval of (628.5 to 661.5 hours)

6 0

3 years ago

What is the slope of a line that<br> contains the points (4, 3) and (-1, -4)?

liq [111]

Answer:

I believe its -7/5 unless they want -7/-5

Step-by-step explanation:

(4,3) (-1,-4)

X1,y1 x2,y2

And it should be

Y2-y1

X2-x1

-4-3 = -7

Over

-1-4 = -5

So -7/5 or -7/-5 whatever your teacher perfers

Hope this helps

3 0

3 years ago

A company pays $3.91 million to air a 30- second commercial during a football game that is watched by approximately 115 million

Radda [10]

Answer:

Part 1) The cost per second is $\$130,333.33$

Part 2) The cost per customer is $\$0.034$

Step-by-step explanation:

Part 1) Calculate the cost per second

we know that

To find out the cost per second, divide the total cost by the time

Let

x ----> the total cost

y ----> the time in seconds

we have

$x=\$3,910,000$

$y=30\ sec$

$\frac{\$3,910,000}{30}=\$130,333.33$

therefore

The cost per second is $\$130,333.33$

Part 2) Calculate the cost per customer

we know that

To find out the cost per customer, divide the total cost by the number of customers

Let

x ----> the total cost

y ----> the number of customers

we have

$x=\$3,910,000$

$y=115,000,000\ customers$

$\frac{\$3,910,000}{115,000,000}=\$0.034$

therefore

The cost per customer is $\$0.034$

6 0

4 years ago

Help! Which choice is the most efficient first step to solve this set of equations?

Dmitry [639]

Answer:

Substitute 3x - 5 for y in the second equation.

Step-by-step explanation:

Generally, to solve the system of linear equations of x and y, the first step would be trying to eliminate x (or y).

Then turn the system into the equation of only y (or x).

Next, try to solve for y (or x).

Then substitute the solved y (or x) into the original system to work out x (or y).

**********

3 options (1 addition, 2 subtractions) do not eliminate x or y (x and y still exist after manipulation).

=> Remaining option relating substitution would be a reasonable choice.

5 0

3 years ago