In a store window, there was a box of berries having a total weight of 200 kg. The berries were 99% water, by weight. After two days in the sun, the water content of the berries was only 90%, by weight. What was the total weight of the berries after two days, in kg?
You're starting with 200 kg of berries, and 99% of that is water.
Since they're 99% water, that means that there's 1% of solid stuff.
1% of 200 kg means that there are 2 kg of solid stuff.
Some of the water evaporates in the sun, but the solid stuff doesn't.
So, after the evaporation, there still remains the same 2 kg of solid stuff.
Since the new water content is 90%, that means that now the solid stuff is 10%.
So 2 kg (the solid stuff) is 10% of the total weight.
That means the new total weight is 20 kg.
.
