Надо , а 20 решите .собственная скорость теплохода 31 км/ч, скорость течения реки 2 км/ч.сколько всего километров теплоход проходит за 3 ч по течению реки и за 4 ч против течения реки?

1.our friends were thought by us all time 

2.he will be operated by the doctor in a week

3.the pupil's parents were sent for by the teacher 

4.the newspaper was looked for by them everywhere

5.nobody was slept in the bed 

6. the telegram was asked for by the neghbor 

7. the lecturer was listened to by everybody with great attention

8. the freshman was laughted at by the senior students 

9. the headmistress was spoken by the group yesterday

10. their   babies   were looked after by the young mothers with great care 

1)248: 4=62(км/ 1 грузовой машины

2)62+8=70(км/ 2 грузовой машины

3)70*7=490(км)-2 грузовая машина за 7 часов

ответ: 490 км проедет вторая грузовая машина за 7 часов.

                                                                                                                                                          : -)