58
Unit 2 | 21 Measure | Student Book chapter 17
21 Measure
Metric conversions
G
1000
km
m
100
10
cm
a Convert 3.852 km to mm.
mm
b Convert 14 297 cm to km.
km to m (3 1000), m to cm (3 100),
cm to mm (3 10)
a 3.852 3 1000 3 100 3 10
5 3852 3 100 3 10 5 3 852 000 mm
b 14 297 4 100 4 1000
Divide when moving to the left in the above diagram.
5 142.97 4 1000 5 0.14297 km
Metric–imperial equivalents
F
3 1 000 000 5 move the
3 d.p. and add three zeros.
4 100 000 5 move the decimal
point 5 places to the left..
You need to learn the following conversions:
Metric
1 kg
1 litre
1 metre
8 km
Imperial
2.2 pounds
1.75 pints
39 inches
5 miles
Imperial
1 ounce
1 gallon
1 foot
1 inch
Metric
25 g
4.5 litres
30 cm
2.54 cm
Carla travels 20 miles to her work.
How many kilometres does Carla travel?
D
Show the
examiner
you know the
conversion. You
will get a mark
for this.
5 miles 5 8 km
20 miles 5 (5 3 4) miles 5 (8 3 4) km 5 32 km
Metric – speed
a A train takes 1 hour 15 minutes to go 100 miles.
What is the average speed of the train in mph?
b Another train has an average speed of 150 km/h and travels for 30 minutes.
What distance does it travel?
a S 5 D 4 T 5 100 miles 4 1 h 15 min
5 100 4 1.25 5 80 mph
Show the speed
multiplied by the
time with the
given units.
b D 5 S 3 T 5 150 km/h 3 30 minutes
5 150 3 0.5 5 75 km
1
2
Show the distance divided by
the time with the given units.
Convert 1 h 15 min to 1.25 hours.
Convert 30 min to 0.5 hours.
Now try these
G
You could just write 20 4 5 3 8
Questions on this spread are targeted at the grades indicated.
Convert:
a 62.3 cm to mm
b 81.7 m to km
c 7.192 kg to g
d 54 litres to ml.
Convert:
a 4321 mg to g
b 342 049 cm to km
c 27 429 ml to kl
d 2.0453 kg to g.
Unit 2 | 21 Measure | Student Book chapter 17
3
Convert:
a 8 ounces to grams
59
G
b 10 kg to pounds
c 10.5 pints to litres
d 40 miles to kilometres.
The length of a piece of wood is 5 ft 4 inches.
Convert this length to centimetres.
6
Two shops sell milk. Shop A charges £3.50 per litre and shop B charges £2.50 per pint.
Which shop sells the cheaper milk? Explain your answer.
E
7
Daley ran 24.5 km at a speed of 7 km/h.
How long did it take Daley to run the 24.5 km?
D
8
Hajra cycles for 3 hours at an average speed of 14 km/h.
Work out the distance that Hajra cycles.
9
Nimer starts walking from his home to his work at 11.20 am. His work is 1.4 km from home.
He gets to work at 11.50 am.
Work out the speed, in km/h, that Nimer walks.
10
The diagram shows the distance, in miles,
Toddington
between some services on the M1 motorway.
26
Scratchwood
a Uzma drives to Toddington from
70
Watford Gap
Watford Gap in 1 hour 15 minutes.
108
83
39
Woodall
Work out her average speed.
b Graham leaves Toddington on his motorbike at 9 am and drives directly to Woodall at a speed of 24 mph.
What time does he arrive?
c Jean leaves Scratchwood at 5 pm.
She drives at an average speed of 66 mph and arrives at Watford Gap at 5.40 pm.
Work out the distance between Scratchwood and Watford Gap.
5
Mabintou weighs 165 pounds.
Work out Mabintou’s weight in kilograms.
F
4
AO2
No.2
The motorway speed limit in Great Britain is 70 miles per hour.
The motorway speed limit in Spain is 120 kilometres per hour.
Which of these speed limits is the lower speed?
You must show working to explain your answer.
(3 marks)
(June 2007)
Great Britain
Spain
The correct answer here is 70 mph but just writing this without a reason got no marks.
To get the 3 marks, there are three stages you must show:
Give a relationship between miles and kilometres: 5 miles 5 8 kilometres
Convert one of the speeds into the other unit.
So either: 70 mph 5 (70 4 5) 3 8 5 14 3 8 5 112 km/h
Or
120 km/h 5 (120 4 8) 3 5 5 15 3 5 5 75 mph.
The third is to give your conclusion. 70 mph is the lower speed. Make sure you have read the question correctly too – you don’t
want to lose a mark just because you assumed it was asking for the higher, whereas actually it is asking for the lower speed.
No.10
Write down the number of pounds in 1 kg.
(1 mark)
(June 2007)
This is something that you just should have learnt. Be sure to learn all your metric to imperial
conversions. 1 kg 5 2.2 pounds.
AO3
AO3
C