Algae is about 90% water. The water content in mosses and lichens is 18 times less.

Algae is about 90% water. The water content in mosses and lichens is 18 times less. Determine the water content in 1 kg of moss.

First of all, let’s determine the percentage of water in algae and mosses, if it is 18 times less than 90%:

90: 18 = 5%.

Having made the proportion, we calculate how many grams of water 1 gram of moss contains, if it is 5% of its mass. 1 kg = 1000 gr:

x = 5%,

1000 gr = 100%.

Let’s write the equation, acting according to the “cross” rule and find the value of the variable:

x = 5 * 1000: 100 = 5000: 100 = 50 grams of water.