Thank you for your letter. I'm sorry for not writing you for so long. I spent time helping my dad.
I've heard about the environmental protection, too. To save the environment every spring we do some cleaning measures in the park and near the sea side. Also we are fighting for recycling which is not very developed in our country. Unfortunately, our local community is not interested much in the environmental problems, so sometimes it’s hard to do important actions without assistance. But despite that fact, the Green Movement in my city is pretty large and it’s still multiplying.
Anyway, tell me about your exams. What do you plan to do next? How much free time have you got ahead? Is there any chance you are going to visit my country?
I've got to go as my friend is asking me for help.
Объяснение:
Dear Ann,
Thank you for your letter. I'm sorry for not writing you for so long. I spent time helping my dad.
I've heard about the environmental protection, too. To save the environment every spring we do some cleaning measures in the park and near the sea side. Also we are fighting for recycling which is not very developed in our country. Unfortunately, our local community is not interested much in the environmental problems, so sometimes it’s hard to do important actions without assistance. But despite that fact, the Green Movement in my city is pretty large and it’s still multiplying.
Anyway, tell me about your exams. What do you plan to do next? How much free time have you got ahead? Is there any chance you are going to visit my country?
I've got to go as my friend is asking me for help.
Write back soon.
Best wishes,
Bob
Объяснение:
На 30-той секунде локомотив въехал на мост, и на 60 секунде последний вагон выехал с моста.
54 км/ч = 54/60=900 м/мин
За 30 сек (полминуты) поезд расстояние:
900/2=450 м.
Этот путь складывается из длины моста и длины поезда.
Известно что длина моста составляет 1 часть а длина поезда 2 части этого пути.
Находим 450 /3=150 метров - это одна часть пути = длина моста
тогда длина поезда составит 150*2=300 м.
Длина одного вагона равна 25 метров, тогда в поезде всего 300/25=12 единиц подвижного состава, то есть 11 вагонов и 1 локомотив.