Page 351 - Start Up Mathematics_7

Solve Mentally Chapter 17
True or False
Exercise
1. False 2. True 3. False 4. True 5. False
1. (a) most likely (b) equally likely (c) equally likely
6. True 7. False 8. True 9. False 10. True
(d) impossible (e) certain (f) not likely
11. True 12. True 1 1
Fill in the Blanks 2. (a) 1 (b) 0 (c) 1 (d) 0 (e) 1 (f) 2 (g) 2
1. 3, 2.5 2. median 3. 50 4. 60 3. (a) 1 (b) 2 (c) 8
5. frequency 6. 50 7. 10 hours 8. 15.4 hours 3 3 15
4. (a) HH, HT, TH, TT (b) HT, TH, TT (c) HT, TH
9. 1 : 2 10. 4 hours 11. 14 hours 12. 21 hours
32
(d) 1, ,
Answer in One Word or a Line 44
1. The number of times a particular value occurs in a data 2 2 1 4
is called its frequency. 5. (a) 11 (b) 11 (c) 11 (d) 11
2. 45 runs 3. 10 1 1 3 1 1
6. (a) (b) (c) (d) (e)
4. The value which occurs maximum number of times is 2 13 4 13 52
called mode.
Review Exercises
5. The value of the variable corresponding to the bar of Multiple Choice Questions
highest frequency gives us the mode.
1. c 2. d 3. a 4. c
6. Yes 7. Mode
5. a 6. b 7. a 8. a
Let’s Evaluate
Solve Mentally
1. (a) 49.5 (b) 50.5 (c) 25
True or False
2. increase by 1.75 years 3. 31
1. True 2. False 3. True 4. False
4. (a) median (b) mode (c) mean
5. True 6. True 7. True
5. 2, 3, 4, 4, 5, 6; No
Fill in the Blanks
Thinking Skills
1. impossible 2. 0, 1 3. sample space
1. (a) 15 km (b) 11 km/litre
4. 1 5. 1 6. equally likely
2. (a) Mean = 152.05 (b) Median = 150 2
(c) Mode = 142 7. event 8. equal
3. (a) 495 kg (b) 55 kg (c) G Answer in One Word or a Line
(d) 4 persons; H, B, F and D (e) H and I 1. 1 2. 1 3. 1 4. 0
4. (a) Sujoy = 8.4, Devika = 6, Jessica = 8.86, Jessica 2 2
(b) The medians are 8.8, 7.5 and 9 respectively. Let’s Evaluate
 Jessica still remains the best player. 1. (a) R (b) T (c) P (d) Q (e) S

(c) Yes, by comparing their highest scores. (d) 8 2. (a) 1 (b) 1 (c) 1 (d) 1
Values and Life Skills 2 4 13 26
1. 33 min 2. 17 hours 3. (a) 1 (b) 1 (c) 5 (d) 1
6 36 12 2
Exemplar Problems 1 1 1 1
4. (a) (b) (c) (d)
1. a 2. minimum; maximum 8 2 4 2
3. False 4. False 5. False 1 1
5. (a) (b) (c) 0 (d) 1
6. (a) 25 (b) 30.41 (c) 33 3 2
7. (a) 8 or 17 or 16 (except 15) 6. (a) 4 (b) 1 (c) 1 (d) 4
(b) Two times 15 (c) Three times 17 9 36 9 9

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