WJEC MATHEMATICS
INTERMEDIATE
MEASURES
COMPOUND MEASURES
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Contents
Speed Distance Time
Density Mass Volume
Population Density
Credits
WJEC Question bank
http://www.wjec.co.uk/question-bank/question-search.html
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Speed Distance Time
When calculating speed, distance, or time we use the following
triangle.
To calculate each of these, we use the "cover up" method.
Example 1
A car travels at 30 mph for 2 hours 15 minutes. How far does it
travel?
Careful!
2 hours 15 minutes is NOT 2.15 hours
2 hours 15 minutes is 2 and a quarter hours = 2.25 hours
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Example 2
An ant travels 50 metres in 2 minutes. What is his speed in km/hr
metres/minute
We have an answer here, however, our units are wrong. To convert
from metres/minute to metres/hour, multiply by 60
metres/hour
However, we require km/hour so divide by 1000
km/hr
Exam Questions G43
1.
2.
3.
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Density Mass Volume
When calculating density, mass, or volume we use the following
triangle.
To calculate each of these, we use the "cover up" method.
MASSIVE clue in the
question! you need a value
in grams and divide it by a
value that's cm3
Example 1
2 litres of oil has a mass of 500g, what is its density in g/cm3
Remember your
conversions!
1000cm3 = 1 litre
So, 2000cm3 = 2litres
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Example 2
A metal object has mass 2kg and has a density of 2g/cm3. Calculate
its volume.
Exam Questions G44
1.
2.
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3.
4.
5.
6.
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Population Density
Population density is a measurement of population per unit area or
unit volume
For example
 The number of people per square km
 The number of bacteria per mm3
 The number of freckles per square cm
Population
Density =
Example
Ewan thinks that the population density of the Vatican City is similar
to Bahrain. He was given the following information. Is Ewan correct?
Show all your workings.
Country
Area (km2)
Population
Vatican City
0.44
800
Bahrain
757
1472483
Vatican City
Bahrain
Ewan is correct, the population densities are similar
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Exercise G28
1. What is the population density of a city with population 4965 and
an area of 12.4km3?
2. What is the population density of a city with population 485 and an
area of 0.61km3?
3. What is the population density of a city with population 478455
and an area of 594km3?
4. What is the population density of a city with population 5994 and
an area of 9.8km3?
5. What is the population density of a city with population 115484
and an area of 6258165km3?
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