Сколько граммов 25 %-ного сахарного сиропа надо добавить к 200 г воды, чтобы концентрация сахара в полученном растворе была 5 %?

1. Have all the voyages of Thor Heyerdahl been much written about?
All the voyages of Thor Heyerdahl haven't been much written about.
2. Has this work been done successfully?
This work hasn't been successfully done.
3. Has the latest football match been criticised?
The latest football match hasn't been criticised.
4. Has this equipment been much spoken about?
This equipment hasn't been much spoken about.
5. Has a new spaceship just been launched?
A new spaceship hasn't just been launched.

1. Had we been informed of the accident before the news about it was published?
We hadn't been informed of the accident before the news about it was published.
2. Had everything been prepared for the examination when we came into the classroom?
Everything hadn't been prepared for the examination when we came into the classroom.
3. Had the tennis competition winner been announced by four o'clock yesterday?
The tennis competition winner hadn't been announced by four o'clock yesterday.
4. Had the patient been examined by a lot of doctors before the operation?
The patient hadn't been examined by a lot of doctors before the operation.