A bottle of instant coffee weighs 600 grams net, and each cup of coffee needs 9 grams of ground coffee and 2 to 5 grams of sugar. What's the maximum number of cups of coffee in this bottle? How many sugar cubes are needed?

0.333 kg.

There are many kinds of algorithms are very simple, only one algorithm is provided here: each cup of coffee needs 6 grams of coffee powder and 4 grams of sugar cubes, that is, each consumption of 6 grams of coffee powder needs 4 grams of sugar cubes, the ratio is: 2\/3, and then multiplied by the total weight of coffee powder, the number of sugar cubes required to finish the coffee powder: 0.333KG.