1. ©2009 – Not to be sold/Free to use
Stage 5
Year 9
Rational
Numbers
Rates
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©2009 – Not to be sold/Free to use

2. A Rate is a comparison of two unlike quantities
Rates
A Rate is a comparison of two unlike quantities
e.g. 60 km /h 
Distance 
Time
e.g. $12
for 8 kg 
Money 
Mass
e.g. 5000kg
in 10 L 
Mass 
Capacity (Volume) 2

3. Rates - Simplifying Example 1: $300 in 6 hours  
Divide the 1st number 
by the 2nd number.
= 300  6
= $50/h
Example 2: 1000 kg in 5 minutes 
Divide the 1st number 
by the 2nd number.
= 1000  5
= 200 kg/min 3

4. Rates - Converting Example 3: Convert 48 kg/day to kg/h
1 day = 24 hours
= 48 kg in 24 hours
= 48  24
= 2 kg/h
Example 4: Convert $3/min to $/h 
1 hour = 60 minutes
= $3 per 1 min
= $(3 x 60) per (1 x 60) min
= $180 per 60 min
= $180/h 4