7th Grade Math

Selected Answers and Solutions R25

Selected Answers and Solutions

For Homework Help, go to Hotmath.com

p

_28,000,000 = _ 10032 Percent proportion

100 p = 32 · 28,000,000 Find cross products.

100 p = 896,000,000 Simplify.

100 p

_ 100 = 896,000,000_ 100 Divide each side by 100.

p = 8,960,000

About 8.96 million teens would buy a music CD if

they were given $20.

3a. about 1,419 people 3b. about 581 people

55 Since 27 MP3s is a part of 238 MP3s, and you

are looking for a percentage, answer c matches this

situation.

7. b 11. Sample answer: Randomly select a part of
   the group to get a sample. Find their preferences,
   and use the results to fi nd the percent of the total
   group. It makes sense to use a sample when
   surveying the population of a city. 13. G 15a. 44%
   15b. 86% 17. _^13 19. 40,320

Pages 474–476 Lesson 8-3F

1. The conclusion is invalid. This is a biased
   sample, since people in other states would spend
   much more than those in Alaska. The sample is a
   convenience sample since all the people are from
   the same state.
   33 This is a simple random survey because each
   person is randomly chosen for the survey, so the
   sample is valid; 42 people.


2. The conclusion is not valid. This is a biased
   sample, since only art club members were
   surveyed. This is a convenience sample.
   77 The conclusion is valid. This is an unbiased,
   simple random sample because randomly selected
   Californians were surveyed.


3. This is a simple random survey, so the sample is
   valid; about 205 people. 11. Sample answer: If the
   questions are not asked in a neutral manner, the
   people may not give their true opinions. For example,
   the question, “You really don’t like Brand X, do you?”
   might not get the same answer as the question, “Do
   you prefer Brand X or Brand Y?” Also, the question,
   “Why would anyone like rock music?” might not get
   the same answer as the question, “What do you think
   about rock music?” 13. Sample answer: A survey
   uses an actual sample to predict the results in a
   population. 15. F 17. 16 pizzas

Pages 477–481 Chapter Study Guide and Review

1. true 3. false; multiplication 5. false; complement


2. false; outcome 9. ^16 11. ^1318 13. 8%

15.

QFQQFSPOJ

XBUFS

#FWFSBHF

QFQQFSPOJ


XBUFS

1J[[B 4BNQMF
4QBDF

KVJDF QFQQFSPOJ


KVJDF

NJML QFQQFSPOJ


NJML

NVTISPPN

XBUFS NVTISPPN


XBUFS

KVJDF NVTISPPN


KVJDF

NJML NVTISPPN


NJML

DIFFTF

XBUFS DIFFTF


XBUFS

KVJDF DIFFTF


KVJDF

NJML DIFFTF


NJML

17. 36 19. 60 21. 120 23. 421 25. 152 27. _ 454


18. _ 258 31. 12 33. about 208 freshmen


19. 162 teens 37. about 204 students

Chapter 9 Statistical Displays

Page 488 Chapter 9 Are You Ready?

1. Rihanna; Ty 3. 25%
   Pages 493–496 Lesson 9-1B


2. 5; 3.5; 0 3. 17.5; 14.5; 14 5. mean; Sample
   answer: no extreme values; $24.38
   77 mean:
   25 ___ +^23 +^23 +^27 +^39 + 1027 +^23 +^31 +^26 +^28 = ^27210
   or 27.2
   median: 23, 23, 23, 25, 26, 27, 27, 28, 31, 39;
   ↓
   26.5
   mode: There are more 23 year olds than players of
   any other age.


3. 27.4; 24; no mode 11. mean 13. Sample
   answer: The mean is 20.65, the median is 20, the
   modes are 15, 20, and 25, and the range is 37. The
   mean or median would best represent the data.


4. 78
   1919 mean:
   3 + ___^5 +^8 +^2 +^1 +^1 + 712 + 3 +^9 + 2 +^3 +^10 =^54 12
   or 4.5
   21a. Sample answer: 3, 4, 5, 8 21b. Sample answer:
   8, 9, 10, 10, 11, 12 23. 35, 41, 44 25. A 27. H
   Pages 500–503 Lesson 9-2A
   1a. 3.5 1b. 8.9; 7.6; 9.5 1c. 1.9 1d. none
   33 a. To fi nd the range, subtract the lowest number
   of golf courses from the highest: 1,465 - 437 or 1,028.
   b. Put the data in order from least to greatest.
   437, 456, 513, 650, 893, 954, 1,018, 1,038, 1,117, 1,465
   Median: Since there is an even number of states
   represented, average the middle two numbers to
   find the median: 893 + 2 954 =^1847 2 or 923.5.

R01_R42_EM_SelAns_895130.indd R25 1/18/10 9:51 AM