Вопрос школьника по предмету Математика
Два самолета вылетели с аэродрома в одно и то же время в противоположных направлениях через 10 мин после вылета расстояние между ними было 270 км Первый самолет летел со срдней скоростью 15 км/мин с какой средней скоростью летел 2 самолета
Ответ учителя по предмету Математика
270/10=27 км/мин-скорость удаления самолетов
27-15=12 км/мин- скорость второго
Похожие вопросы от пользователей
It’s a wonderful world we live in. For thousands of years the Earth has given support to all forms of life – human beings, animals, birds, fishes, insects and plants.But now human beings are killing our planet.Many species of animals and birds have disappeared. Millions of animals die every year because man has polluted their natural homes. Besides, every year people cut down more trees, build more roads, and use more land for farming. This leaves fewer jungles, fields and forests for wildlife.The country air, once clear and fresh, now may be polluted by power stations and factories. Some of our rivers are now empty of fish. And in some rivers you can even see a sick foam(пена) caused by chemical waste.All over the world the forests are disappearing. People cut the trees down because they need wood and paper or new places for farms and houses. Forests the size of Belgium are destroyed every year. It’s an international disaster. Even if new trees are planted, it takes many years for them to grow.Go to the seaside and you’ll see the pollution around you. There is a lot of litter on the beaches. Some of it was left by people and some was brought by the water.Pollution is very dangerous for people, wildlife and the environment.We live among litter and wastes which we have created ourselves – fumes of cars, throwaway packaging, etc. People don’t just pollute the environment. They pollute themselves with cigarettes, alcohol and junk food. These are some of the world’s most serious environmental problems. And it’s no good pretending they don’t exist – they do. What’s more, they are getting worse all the time. What will happen if we don’t try to solve these problems? Scientists have made predictions and they are alarming.