автомобиль должен проехать 840 км за определенное время. На половине пути он был задержался на 30 мин из за технической неисправности. Чтобы прибыть вовремя, ему пришлось увеличить скорость на 2км/ч. Сколько времени автомобиль находился в пути?

преобразуйте выражение в дробь объясните пожалуйста срочно m+1/n

Замените действительный залог страдательным.
А) 1. Many people attend the lecture. 2. Someone has eaten the cake. 3. He will leave the ticket on the table. 4. They were discussing the report the whole evening. 5. People speak English in many countries. 6. Snow will cover the fields in winter. 7. Everyone can see the film soon. 8. The gardener has planted some apple –trees. 9. His parents have bought him a new bicycle. 10. They will advertise the product on TV.
В) 1. An actor killed President Abraham Lincoln. 2. Alexander Bell invented the telephone. 3. The Chinese invented paper. 4. They invented photography. 5. The French government gave the Statue of Liberty to the American people. 6. Shah Jahan built the Taj Mahal mausoleum for his wife who died in 1631. 7. They make Volkswagen cars in Germany. 8. Columbus discovered America. 9. Fleming discovered penicillin. 10. They talked much about that problem.

цена авиабилета понижена на 25%  и  составила 1575руб. какова была цена билета до понижения цены?

помогите!!!решить 2 уравнения: (80-х)*5+20=370 и (640:у)*9-27=45