Рассчитайте, какую массу воды необходимо взять для приготовления раствора с массовой долей вещества 20%, если нужно растворить 100 г соли

1. I have a half-brother, we like to spend time together, but I prefer to live with her mother .2 . In my country, people go to university and get a first job when they turn 20 years old, and dismissed when they are 60 .3.He crazy about collecting musical instruments. His collection is very valuable and is worth 300,000 pounds.4 . During the day she washed and ironed , and in the evening went shopping .5.Each housework I usually perform . Always wash the dishes and help in the garden / gardening mom , but I like to do the household chores with his brother6.They tall and can bend to reach the doorbell .7. She has to bend down to get it done