Первая труба заполняет бассейн с водой за 10ч, а вторая за 8ч. Некоторое время обе трубы вместе наполняли бассейн, а затем 1 час первая труба была отключена. В результате бессейн был наполнен на 80%. Какое время работали 2 трубы одновременно?

1)    Tom offered me a job.

2)     Someone has shown Tom the new apartment.

3)    The boss pays Tom $100 every week.

4)    They asked me difficult questions at the exam.

5)    Sasha is telling Tom a joke.

6)    We often speak about her.

7)    The doctor will operate on him in a week.

8)    Everybody listened to the lecturer with great attention.

9)    The boys will paint the roof of the house.

10)  They are preparing a report now.

11)  By the middle of autumn we had planted all the trees.

12)  They have forgotten the story.