Because theoretical and experimental probabilities are ratios, we can use proportions with probabilities to make predictions.

 

The results of a random survey of 8th grade students at Summit Middle School showed that 32 out of 70 students prefer listening to country music. If there are 490 students in the 8th grade at Summit Middle School, approximately how many students would be expected to prefer listening to country music?

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Drag the tiles to set up a proportion that can be used to solve this problem.

Solve the proportion that you set up in order to determine the answer to the original question,
How many students would be expected to prefer listening to country music?

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Hint

What factor can be multiplied by 70 in order to obtain 490? Multiply 32 by this same factor.Close Pop Up Interactive popup. Assistance may be required.

Check Your Answer

You would expect 224 students to prefer listening to country music. Close Pop Up

Practice

  1. The probability that one wristband is defective is 1 over 20 1 20 . In a case of 840 wristbands, how many would be defective?
    2. Interactive popup. Assistance may be required.

    Hint

    Set up a proportion with two equivalent ratios: number of defective wristbands to total number of wristbands.Close Pop Up Interactive popup. Assistance may be required.

    Check Your Answer

    42Close Pop Up
  2. Benita observed that 28 out of 55 patrons at the public library used the computer. The librarian told Benita that 660 patrons enter the library throughout the day. Based on Benita's observations, how many patrons during the day would be expected to use the computer?
    3. Interactive popup. Assistance may be required.

    Hint

    Set up a proportion with two equivalent ratios: number of patrons using the computer to total number of patrons.Close Pop Up

    Use the grid below to record your answer. Type your answer in the boxes in front of and behind the decimal. Click inside each box to enter the numeral that belongs in the box, and then click the bubble beneath the numeral to shade the bubble that matches the numeral. After hitting the "Submit" button, incorrect portions of your answer will be shaded gray.

    Interactive exercise. Assistance may be required.

  3. Clayton selected number tiles out of a bag. He recorded his results in the table.
Number Tile Selections
Number
Frequency
1
6
2
4
3
5
4
8
5
7
6
10

Based on these results, if Clayton draws 100 tiles, how many odd numbers should he expect to draw?

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Hint

Set up a proportion with two equivalent ratios: number of times that an odd number was drawn to total number of draws. Close Pop Up Interactive popup. Assistance may be required.

Check Your Answer

45Close Pop Up