7.Сколько может быть элементарных событий при одновременном бросании двух игральных костей 1 в раз? Чему равна вероятность выпадения очков, сумма которых равнялось бы 5 ?
1. She found £10 beneath the sofa. 2. James filled to the police to report the incident. 3. He dived into the swimming pool twice. 4. He told me the truth. 5. I watched the last episode of my favourite TV series yesterday. 6. She sended him a present by post. 7. Mary crying a lot when she heard the bad news. 8. Brian went the train to London. 9. She felt happy when she got her jewels back. 10. Peter dropped my mother's antique vase. It broke into thousands of pieces. 11. Laura сalled her mother as soon as she arrived in Paris. 12. He stoped talking when I walked into the room. 13. She tryed to stop the thief, but he got away. 14. She took the glass with orange juice. 15. Miss Marple solved many mysteries in St Mary Mead.
Ну попробуем так: а (анна) спела 8 песен. б (берта) спела х песен в (вита) спела у песен д (дороти) спела 5 песен так? теперь самое главное: каждую песню пели 3 девочки, так? значит 8 + х + у + 5 должно делиться на 3. это понятно? и мы знаем, что х меньше 8, но больше 5. то есть х = 6 или х = 7 точно так же у = 6 или у = 7 считаем: если х = 6 и у = 6, то 8 + х + у + 5 = 25, на три не делится. если х = 6, а у = 7, то 8 + х + у + 5 = 26 на три не делится. а если х = 7 и у = 7, то 8 + х + у + 5 = 27 делится на 3, и 27 : 3 = 9. то есть всего спели 9 песен.
1. She found £10 beneath the sofa.
2. James filled to the police to report the incident.
3. He dived into the swimming pool twice.
4. He told me the truth.
5. I watched the last episode of my favourite TV series yesterday.
6. She sended him a present by post.
7. Mary crying a lot when she heard the bad news.
8. Brian went the train to London.
9. She felt happy when she got her jewels back.
10. Peter dropped my mother's antique vase. It broke into thousands of pieces.
11. Laura сalled her mother as soon as she arrived in Paris.
12. He stoped talking when I walked into the room.
13. She tryed to stop the thief, but he got away.
14. She took the glass with orange juice.
15. Miss Marple solved many mysteries in St Mary Mead.
GOOD LUCK