Step: 1

Let x be the number of defective disks.

Step: 2

(Number of defective compact disks in the sample) / (Total number of disks in the sample) = (Number of defective disks in a sample of 2000 disks) / (Total number of disks)

Step: 3

[Write a proportion.]

Step: 4

[Write the cross products.]

Step: 5

= 80

[Simplify.]

Step: 6

Chris can expect 80 disks to be defective in a sample of 2000 disks.

Correct Answer is : 80

Step: 1

Let the number of doorbells defective in a sample of 15,000 doorbells be y .

Step: 2

Doorbells defective in a sample of 150 doorbells / Number of doorbells = Doorbells defective in a sample of 15,000 doorbells / Number of doorbells

Step: 3

[Write the proportion.]

Step: 4

[Write the cross products.]

Step: 5

= 600

[Simplify.]

Step: 6

Number of doorbells defective in a sample of 15,000 is 600.

Correct Answer is : 600

Step: 1

Let y be the number of pairs defective out of 250 pairs.

Step: 2

Step: 3

[Substitute.]

Step: 4

[Write the cross products.]

Step: 5

= 50

[Simplify.]

Step: 6

The shoe manufacturer can predict 50 pairs of defective shoes.

Correct Answer is : 50

Step: 1

Let y be the number of students who like football out of 2500.

Step: 2

Write a proportion.

Step: 3

[Substitute.]

Step: 4

[Write the cross products.]

Step: 5

= 850

[Multiply.]

Step: 6

850 out of 2500 students like football.

Correct Answer is : 850

Step: 1

From the graph, the distance that Justin covers is increasing in each hour.

Step: 2

The distance that Justin covers in 15 hours is 150 mi.

Step: 3

So, one would expect the distance that Justin covers in 20 hours to be certainly greater than 150 mi.

Correct Answer is : Greater than 150 mi

Step: 1

Let y be the number of people who like wrestling out of 2000.

Step: 2

Number of people who like wrestling out of 100 people / Total number of people = Number of people who like wrestling out of 2000 people / Total number of people

Step: 3

= 23 100 = y 2 0 0 0

[Substitute.]

Step: 4

[Write the cross products.]

Step: 5

= 460

[Simplify.]

Step: 6

460 out of a population of 2000 people like wrestling.

Correct Answer is : 460

Step: 1

Let y be the number of people who like football out of 1000.

Step: 2

Number of people who like football out of 100 people / Total number of people = Number of people who like football out of 1000 people / Total number of people

Step: 3

= 34 100 = y 1 0 0 0

[Substitute.]

Step: 4

[Write the cross products.]

Step: 5

= 340

[Multiply.]

Step: 6

340 out of a population of 1000 people like football.

Correct Answer is : 340

Step: 1

Let x be the number of students in the entire school who prefer dance class to music class.

Step: 2

Total number of students in the school = 600

Step: 3

Step: 4

So, 320 students in the school prefer dance class to music class.

Correct Answer is : 320

Step: 1

Prediction means telling what would happen in the near future.

Step: 2

The graph shows an increasing trend in the profit earned by a company (in percent) during the last three years by 10% .

Step: 3

The profit earned by the company (in percent) in the year 2004 is 50%

Step: 4

So, it can be predicted that the profit earned by the company(in percent) for the year 2005 would be 60% .

Correct Answer is : 60 %

Step: 1

The sales have been decreasing each month.

Step: 2

Sales in the month of May are $1,000.

Step: 3

So, one would expect the sales in June to be less than $1,000.

Correct Answer is : less than $1,000

Step: 1

From the bar graph, the difference in the population of a country in succeeding years is 50%.

Step: 2

So, the population in the year 2003 would be about 260 million.

Correct Answer is : about 260 million

Step: 1

The given graph shows the circulation of a magazine (in thousands) in the year 2004.

Step: 2

The circulation of the magazine in the first quarter of 2004 will be about 180, 000.

Correct Answer is : about 180,000

Step: 1

Among 150 people, 75 preferred rock music.

[Given]

Step: 2

That means half of the people preferred rock music.

[As 75 is half of 150.]

Step: 3

So, 300 people out of 600 could be predicted to prefer rock music.

[As 300 is half of the 600.]

Correct Answer is : 300

Step: 1

Number of Toys checked = 500.

Step: 2

Number of Toys found to have defective = 10.

Step: 3

Probability of a Toys to have defective out of 100 = 1 0 5 0 0 N u m b e r o f f a v o u r a b l e e v e n t s T o t a l n u m b e r o f p o s s i b l e o u t c o m e s

Step: 4

[Simplify]

Step: 5

Number of Toys to have defective out of 200 magazines = 200 × 1 5 0

Step: 6

= 4.

[Simplify]

Correct Answer is : 4

Step: 1

Number of T-shirts manufactured every week = 6000.

Step: 2

Number of T-shirts checked = 100.

Step: 3

So, the probability of getting a defective T-shirt = 6 1 0 0

[Number of favorable events Total number of possible outcomes.]

Step: 4

= 3 5 0

Step: 5

Therefore, the number of T-shirts that can have defects in each week of the production = 6000 × 3 5 0

[Simplify.]

Step: 6

= 360

Correct Answer is : 360

- Probability of an Event Represented by a Number From 0 to 1-Gr 7-Solved Examples
- Possible Outcomes-Gr 7-Solved Examples
- Identifying Equally Likely Outcomes-Gr 7-Solved Examples
- Likelihood of an Event-Gr 7-Solved Examples
- Probabilities of Compound Events-Gr 7-Solved Examples
- Making Inferences from Data of Two Populations-Gr 7-Solved Examples

- Data