To make coleslaw Cathy uses twice as much carrot (by weight) as cabbage. She then adds half as much yoghurt as cabbage. A pot of Cathy\textquotesingle s coleslaw weighs $$175\text{g}$$. How many pots of coleslaw can she make with a $$2 \text{kg}$$ cabbage? 
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The ratio by weight of carrot: cabbage:yoghurt$$=2:1:0.5$$ which we can double to give $$4:2:1$$. We can see that here $$2$$ represents the amount of cabbage and we want $$2 \text{kg}$$ of cabbage, so there will be $$4+2+1=7\text{kg}$$ of coleslaw altogether. Therefore the number of pots is $$7000\div 175 =40$$. 