В 200 г солевого раствора содержится 10 г соли. Какова концентрация соли в растворе? 2) В 120 г воды растворили 30 г сахара. Какова концентрация сахара в растворе

1.The teacher said that the students had asked about it the previous week.
2. The librarian said that they had opened a new exhibition.
3. The boy cried that he had broken his toy the day before.
4. The pupils said that she was writing a letter at that moment.
5. She said she studied at the University.