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grigory [225]
2 years ago
4

A chemist bought 2390 test tubes and beakers.1034 of them were test tubes and the rest were beakers.How many more beakers did th

e chemist buy than test tubes?
Mathematics
1 answer:
Yuri [45]2 years ago
6 0

Answer:

322

Step-by-step explanation:

The question explains that the total of both test tubes and beakers were

= 2390.

If 1034 of them were test tubes, then the number of beakers bought,

= 2390 - 1034

= 1356.

The question requires the answer to how many more beakers than test tubes were bought, and this would mean subtracting the number of beakers from the number of test tubes.

= 1356 - 1034

= 322

Therefore, 322 more beakers than test tubes were bought.

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A fish market bought two swordfish at a rate of $13 per pound the cost of the larger fish was 3 times as great as the cost of th
Orlov [11]
3952/13 is 304 pounds at the cost of 13 dollars each fish is 152 pounds
6 0
2 years ago
At a used book store, Valentina purchased three books for $2.65 each. If she paid with a $20 bill, how much change did she recei
Oksana_A [137]

Answer:

12.05$

Step-by-step explanation: 2.65$ x 3 - 20$= 12.05$

7 0
2 years ago
A process manufactures ball bearings with diameters that are normally distributed with mean 25.1 mm and standard deviation 0.08
marta [7]

Answer:

(a) The proportion of the diameters are less than 25.0 mm is 0.1056.

(b) The 10th percentile of the diameters is 24.99 mm.

(c) The ball bearing that has a diameter of 25.2 mm is at the 84th percentile.

(d) The proportion of the ball bearings meeting the specification is 0.8881.

Step-by-step explanation:

Let <em>X</em> = diameters of ball bearings.

The random variable <em>X</em> is normally distributed with mean, <em>μ</em> = 25.1 mm and standard deviation, <em>σ</em> = 0.08 mm.

To compute the probability of a Normally distributed random variable we need to first convert the raw scores to <em>z</em>-scores as follows:

<em>z</em> = (X - μ) ÷ σ

(a)

Compute the probability of <em>X</em> < 25.0 mm as follows:

P (X < 25.0) = P ((X - μ)/σ < (25.0-25.1)/0.08)

                    = P (Z < -1.25)

                    = 1 - P (Z < 1.25)

                    = 1 - 0.8944

                    = 0.1056

*Use a <em>z</em>-table for the probability.

Thus, the proportion of the diameters are less than 25.0 mm is 0.1056.

(b)

The 10th percentile implies that, P (X < x) = 0.10.

Compute the 10th percentile of the diameters as follows:

P (X < x) = 0.10

P ((X - μ)/σ < (x-25.1)/0.08) = 0.10

P (Z < z) = 0.10

<em>z</em> = -1.282

The value of <em>x</em> is:

z = (x - 25.1)/0.08

-1.282 = (x - 25.1)/0.08

x = 25.1 - (1.282 × 0.08)

  = 24.99744

  ≈ 24.99

Thus, the 10th percentile of the diameters is 24.99 mm.

(c)

Compute the value of P (X < 25.2) as follows:

P (X < 25.2) = P ((X - μ)/σ < (25.2-25.1)/0.08)

                    = P (Z < 1.25)

                    = 0.8944

                    ≈ 0.84

*Use a <em>z</em>-table for the probability.

Thus, the ball bearing that has a diameter of 25.2 mm is at the 84th percentile.

(d)

Compute the value of P (25.0 < X < 25.3) as follows:

P (25.0 < X < 25.3) = P ((25.0-25.1)/0.08 < (X - μ)/σ < (25.3-25.1)/0.08)

                    = P (-1.25 < Z < 2.50)

                    = P (Z < 2.50) - P (Z < -1.25)

                    = 0.99379 - 0.10565

                    = 0.88814

                    ≈ 0.8881

*Use a <em>z</em>-table for the probability.

Thus, the proportion of the ball bearings meeting the specification is 0.8881.

4 0
2 years ago
The following table shows the annual income, in dollars, and amount spent on vacation, in dollars, for a sample of 8 families.
marishachu [46]

Answer:

a. Scatterplot is attached.

b. Positive Correlation

c. Correlation coefficient=0.9219

Step-by-step explanation:

a.

The following procedure will be used to obtain the scatter plot

  •    Open an Google Sheets file online or excel sheet on your computer.
  •    In column B and C, enter  the Income and Vacation data  as provided above.
  •    Select the data > click on insert CHART.
  •    Chose Scatter Chart option
  •    Click OK.

A scatter plot visualizing your data should be displayed as attached.

b.

  • On your computer, open a spreadsheet in Google Sheets.
  • Double-click on your scatter plot.
  • At the right, click on Customize  tab and then Series.
  • Scroll down and check the Trend line box

-From the trend line, your notice that your variables have a positive correlation.

-As the income increases, so does vacation expenditure.

c. The correlation coefficient can be calculated as follows.

  • Click on any empty cell in the sheet and enter the formula
  • "=CORREL((y-axis range),(x-axis range))"
  • ENTER

-From our Google Sheets calculation our variables have a positive correlation and the correlation coefficient is 0.9219

-The correlation coefficient,r can also be calculated manually:

-let x be income, and y be vacation and divide all the values by 100 to make the smaller and easier to manipulate:

r=\frac{n(\sum xy)-(\sum x)(\sum y)}{\sqrt{[n\sum x^2-(\sum x)^2][n\sum y^2-(\sum y)^2}}\\\\\\\sum xy=153914\\\sum x=4485\\\sum y=246\\\sum x^2=2878447\\(\sum x)^2=4485^2=20115225\\(\sum y)^2=246^2=60516\\\sum y^2=8392\\n=8\\\\\#substitute \ and \ solve \ for \ r\\\\=\frac{8\times153914-4485\times 246}{\sqrt{[8\times 2878447-4485^2][8\times 8392-246^2]}}\\\\=0.92186\\\\\approx 0.9219

4 0
2 years ago
Compute P7,2. (Enter an exact number.)
Katarina [22]

Answer:

42

Step-by-step explanation:

The permutation formula is P(n, r) = n! / (n - r)!. We know that n = 7 and r = 2 so we can write:

7! / (7 - 2)!

= 7! / 5!

= 7 * 6 * 5 * 4 * 3 * 2 * 1 / 5 * 4 * 3 * 2 * 1

= 7 * 6 (5 * 4 * 3 * 2 * 1 cancels out)

= 42

8 0
2 years ago
Read 2 more answers
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