This means that for every 5 kilograms of fruit, you'll get 3 kilograms of sugar.
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Let's divide 8 into 5 parts. 8/5 = 5/5 + 3/5 = 1.0 + 0.6 = 1.6
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1.6 x 3 = 3 + 1.8 = 4.8
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This means that within 8 kg of fruit you'll find 4.8 kg of sugar.