Question

M (H2O)-120 грамм m (соли)-30 грамм W-?

Answer 1

W=100%*30/(120+30)=100%/5=20%
Ответ: 20%

Это только по том, что ты дал(-а), была бы сама задачка-были бы объяснения

Answer 2

It appears that you have given the mass of water (H2O) as 120 grams and the mass of salt (m) as 30 grams. Now, you want to find the mass of something denoted by W.

To proceed, we need more information about the relationship between these quantities. Are they mixed together or in some chemical reaction? Additionally, is there any other information given about the substances involved? Please provide more context so that I can assist you further.