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Look at the following:

a) $20 : $30 = 2 : 3

b) 450 apples : 180 pears = 5 : 2

c) $60/litre

d) 350 boys : 560 girls = 5 : 8

All the examples are ratio except (c). (c) is an example of rate which will be covered in Section 2.

Compare the ratios to (c) and try to come out with a defintion of ratio.     

If you look closely, you will find that the ratios compare 2 like quantities of the same units. Thus,

Ratio is a comparison of 2 like quantities of the same unit.

A photograph that is 12.5 cm by 9 cm is enlarged in the ratio 8 : 5. Find the area of the enlarged photograph.

Area of Enlarged Photograph = ( x 12.5 cm) x ( x 9 cm)                                              = 32 cm x 14.4 cm                                              = 460.8 cm

Read the question below carefully and work it out.

1. The price of a computer dropped from $3200 to $2400. Find out the ratio in which the price decreases.

2. The decreased price of 1 kg of beef is $18.50. The price of beef had decreased in the ratio 9 : 5. Find the original price of 2 kg of beef.