A woman has invited her family for dinner. She has prepared a large pot of vegetable soup as an appetizer. In the morning, she puts it in her yard to cool down and forgets to cover it. The pot contains 100 kg of soup, 98% of which is water. Unfortunately, it starts to rain heavily and the pot is still not covered. At noon, the soup has a water content of 99%.
How much does the soup weigh now?
The soup now weighs 200 kg. In the morning it weighed 100 kg, of which 98% (i.e., 98 kg) was water. This means that only 2 kg (100 kg − 98 kg = 2 kg) of the soup consisted of greens. After the rain, the 2 kg of greens make up only 1% of the total weight (99% is now water). So 1 % corresponds to 2 kg, and 100% corresponds to 200 kg.