1. ©G Dear 2008 – Not to be sold/Free to use
Units of
Measurement
General Mathematics
Preliminary
Rates
Stage 6 - Year 11
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©G Dear 2008 – Not to be sold/Free to use

2. It is the comparison of two (or more) quantities of a different type.
Rates (1/5)
It is the comparison of two (or more) quantities of a different type.
km/h
kg/ha
Kilometres per hour
Kilograms per hectare
Distance
Time
Mass
AreA
mg/L
L/h
Milligrams per litre
Litres per hour
Mass
Volume
Volume
Time

3. To simplify rates we divide the first number by the second.
Simplifying Rates (2/5)
To simplify rates we divide the first number by the second.
Eg 1: 600 km in 5 hours
600 ÷ 5
= 120 km/h
Eg 2: 50 tonne in 10 hectares
50 ÷ 10
= 5 t/ha

4. To convert rates we multiply (or divide) each number separately.
Converting Rates (3/5)
To convert rates we multiply (or divide) each number separately.
Eg 1: Convert 72 km/h to m/s
x 1000 (to convert to meters)
= m/h
(to convert to seconds)
x 60 x 60
= m/ 3600 s
= ÷ 3600
= 20 m/s

5. To convert rates we multiply (or divide) each number separately.
Converting Rates (4/5)
To convert rates we multiply (or divide) each number separately.
Eg 2: Convert 7500 mL/1500g to L/kg
÷ 1000 (to convert to litres)
= 7.5 L/1500g
(to convert
to kilograms)
÷ 1000
= 7.5 L/ 1.5 kg
= 7.5 ÷ 1.5
= 5 L/kg

6. Using Rates (5/5)
A recipe for banana cake (for 6 people) includes 2 bananas, 500g of flour and 100 mL of olive oil.
Convert it for 9 people.
Multiplication Factor = 9
÷ 6
= 1.5
Bananas = 2
x 1.5 =
3 Bananas
Flour =
500
x 1.5 =
750 g
Olive oil =
100
x 1.5 =
150 mL