Edexcel-Igcse-Mathsbook2-Answers
Edexcel IGCSE Maths 2
Answers to activities and exercises
Unit 1
NUMBER 11 ACTIVITY 1
Time (h) Speed (km/h) 1 160 2 80 4 40 6 26.7 7 22.9 8 20
EXERCISE 1
1 a 4 days 2 3 4 5 6 7 8 a a a a a a a 28 days 8 men 12 people 60 years 40 000 men 12 hours 32 km/litre b 2 days b b b b b b b 6 days 16 men 8 people 15 years 20 000 men 72 km/h 20 litres c 2 c c c c c
2 days 3 4.8 days 32 men 6 people 1200 years 400 men
EXERCISE 1*
1 a Number of light bulbs (N) 6 5 2 30 b 3000 = NP 2 a Number of years (N) 1 2 4 10 Number of men (M) 100 000 50 000 25 000 10 000 Power of each bulb (P) 500 600 1500 100
IGCSE Maths Answers – Unit 1
1
b 100 000 = NM 3 a 12 g/cm3 4 a 10 minutes 5 Number of men 100 000 100 000 20 000 400 000 IGCSE Maths Answers – Unit 1 6
b 1.5 cm3 b 12.8 litres/minute Number of tunnels 4 2 8 2 Number of young 18 000 5 9 million 4.5 billion b 1000 b 46 000 tonnes (2 sf) (ii) 30 seconds (iv) 8 seconds Time in years 4 2 40 0.5 Time 1 hour 1 second 1 hour 500 hours c 2.26 108 tonnes c 180 000 tonnes (2 sf)
Number of mosquitoes 1 1 500 500
7 a 5 8 a 16 tonnes (2 sf) 9 a 16 tonnes (2 sf) b (i) 4 minutes (iii) 70 seconds
EXERCISE 2
1 0.375 5 0.28125 9 0.18 13 0.38
3 5 , 20 64 5 21 9 7 25 90 1 29 18
2 0.05 6 0.1375 10 0.36 14 0.94
3 7 9 9 , , , 40 80 25 24 2 22 3 1 26 90 1 30 15
17
18
3 0.08 7 0.2 11 0.26 9 15 16 1 19 3 7 23 9 1 27 30
4 0.1875 8 0.5 12 0.53 5 3 16 , 32 8 4 20 9 24 1 28
1 45
EXERCISE 2*
1 0.46 5 2.30 11 7 3 9 , , 16 40 15 24 13 99
2
2 0.61 6 4.12 7 5 7 10 , , 40 32 8 38 14 99
3 0.046 4 0.161 7 0.301 8 0.280 19 3 5 11 55 9 9 11 12 , , , , , 20 25 64 125 128 512 48 10 31 15 16 33 33
19 990 412 21 999 11 25 90 29 0.037
17 9
29 990 101 22 999 13 26 15 30 0.016
18 8
3 110 128 23 333 28 27 495
19
2 55 158 24 333 31 28 198
20
REVISION EXERCISE 3
2 hours 7.5 km/litre 0.2 0.16 2 5 a 9 1 2 3 4 a a a a 6 mowers 6 litres 0.125 0.4 7 b 90 b b b b c 0.05 c 0.428571 23 c 99 IGCSE
Answers to activities and exercises
Unit 1
NUMBER 11 ACTIVITY 1
Time (h) Speed (km/h) 1 160 2 80 4 40 6 26.7 7 22.9 8 20
EXERCISE 1
1 a 4 days 2 3 4 5 6 7 8 a a a a a a a 28 days 8 men 12 people 60 years 40 000 men 12 hours 32 km/litre b 2 days b b b b b b b 6 days 16 men 8 people 15 years 20 000 men 72 km/h 20 litres c 2 c c c c c
2 days 3 4.8 days 32 men 6 people 1200 years 400 men
EXERCISE 1*
1 a Number of light bulbs (N) 6 5 2 30 b 3000 = NP 2 a Number of years (N) 1 2 4 10 Number of men (M) 100 000 50 000 25 000 10 000 Power of each bulb (P) 500 600 1500 100
IGCSE Maths Answers – Unit 1
1
b 100 000 = NM 3 a 12 g/cm3 4 a 10 minutes 5 Number of men 100 000 100 000 20 000 400 000 IGCSE Maths Answers – Unit 1 6
b 1.5 cm3 b 12.8 litres/minute Number of tunnels 4 2 8 2 Number of young 18 000 5 9 million 4.5 billion b 1000 b 46 000 tonnes (2 sf) (ii) 30 seconds (iv) 8 seconds Time in years 4 2 40 0.5 Time 1 hour 1 second 1 hour 500 hours c 2.26 108 tonnes c 180 000 tonnes (2 sf)
Number of mosquitoes 1 1 500 500
7 a 5 8 a 16 tonnes (2 sf) 9 a 16 tonnes (2 sf) b (i) 4 minutes (iii) 70 seconds
EXERCISE 2
1 0.375 5 0.28125 9 0.18 13 0.38
3 5 , 20 64 5 21 9 7 25 90 1 29 18
2 0.05 6 0.1375 10 0.36 14 0.94
3 7 9 9 , , , 40 80 25 24 2 22 3 1 26 90 1 30 15
17
18
3 0.08 7 0.2 11 0.26 9 15 16 1 19 3 7 23 9 1 27 30
4 0.1875 8 0.5 12 0.53 5 3 16 , 32 8 4 20 9 24 1 28
1 45
EXERCISE 2*
1 0.46 5 2.30 11 7 3 9 , , 16 40 15 24 13 99
2
2 0.61 6 4.12 7 5 7 10 , , 40 32 8 38 14 99
3 0.046 4 0.161 7 0.301 8 0.280 19 3 5 11 55 9 9 11 12 , , , , , 20 25 64 125 128 512 48 10 31 15 16 33 33
19 990 412 21 999 11 25 90 29 0.037
17 9
29 990 101 22 999 13 26 15 30 0.016
18 8
3 110 128 23 333 28 27 495
19
2 55 158 24 333 31 28 198
20
REVISION EXERCISE 3
2 hours 7.5 km/litre 0.2 0.16 2 5 a 9 1 2 3 4 a a a a 6 mowers 6 litres 0.125 0.4 7 b 90 b b b b c 0.05 c 0.428571 23 c 99 IGCSE