đang cần gấp: Trên quãng đường AB, hai ô tô đi ngược chiều nhau và cùng khởi hành thì sau 6 giờ sẽ gặp nhau, biết vận tốc của xe đi từ A bằng vận tốc xe đi từ B. Hỏi xe đi từ A phải khởi hành sau xe đi từ B bao lâu để hai xe có thể gặp nhau ở chính giữa đường.

Các câu hỏi liên quan

ANH 8 – date :27/3/2020- I. Find the word which has a different stress pattern from the others. 1. A. geography  B. electronic  C. scientific  D. preparation 2. A. climatology  B. bibliography  C. communication D. radiography 3. A. zoology  B. biography  C. meteorology  D. photography 4. A. primary  B. animal  C. tropical  D. volcano 5. A. debris  B. rainstorm  C. destroy  D. shelter II. Choose the correct answer A, B, C or D to complete these sentences. 6. If this factory continues _________ poison into the lake, all the fish will die. A. pouring B. dumping C. pumping D. sacking 7. Some tents _______ so that children and old people could sleep in. A. was set up B. were set up C. set up D. setted up 8. When thermal pollution happens, the water temperature in streams, rivers, lakes and oceans_____ A. changes B. keeps C. remains D. stays 9. The sight of too many advertising billboards ov erhead poles and shop signs causes _______ pollution. A. air B. light C. noise D. visual 10. An earthquake is the _______ of a sudden release of energy in the Earth’s crust. A. cause by B. consequence C. result from D. result of 11. ________ you ever been to any English speaking countries? A. Do B. Have C. Were D. Are 12. Scientists have spent years trying ________ weather patterns but it is still an inexact science. A. predicting B. to predict C. to predicting D. to have predicted 13. Australia is home to __________ animals like kangaroos and koalas. A. only B. rare C. unique D. precious 14. We became _______ by rising floodwater. We couldn’t move to anywhere else. A. trapped B. rescued C. reported D. evacuated 15. The government is sending aid to flood _______. A. victims B. people C. villagers D. residents III. Complete the sentences with the correct form of the verbs in brackets. 16. Mai (live) ___ in Hai Phong for five years before she (move) ____ to Ha Noi three years ago.