hai người củng đi từ xã A đến xã B, AB=16km, mà chỉ có một chiếc xe đạp không đèo được. vận tốc  của người thứ nhất khi đi bộ và dđi xe đạp lần lượt  là 4km/h vả 10km/h còn của người thứ hai  là 5km/h và 12km/h.Hỏi hai người có  thể thay thế nhau sử dụng xe đạp như thế  nào để xuất phát củng một lúc và đến nơi củng một  lúc.

giải giúp mình nha!!!!

. Complete the second sentence so that it means the same as the first. Use the word in brackets. You may need to change the word.

Here is an example.
0. The bookshop is opposite the library.
    _________________________ a bookshop opposite the library. (THERE)
Answer: There is

1. The English speaking countries exhibition finishes at 8p.m. (END)
_________________________________________________________
2. How long is the presentation? (LAST) _________________________________________________________
3. The photo session takes place in the library. (HOST) _________________________________________________________
4. What time does the HN302 leave? (DEPARTURE) _________________________________________________________
5. A kilt is the traditional garment for Scottish men.(TRADITIONALLY) _________________________________________________________

Rewrite the sentences , using the words in brackets 
1.We are unable to see the stars in the sky.Light pollution accurs (makes) 
2. Contamination in the air happens . There is acid rain which damages soil,vegetation and aquatic life of the region (causes) 
3.Noise pollution is one of the major causes of strees and anxiety . People suffer from stress and anxiety . ( because of) 
4.The oil spill resulted in the death of thousands of fish in this sea ( make) 
5.All the roads were flooded because it had been raining heavily . (due to) 
6.Jimmy ate a lot of fast food , so he put on 10 kilograms within just two months (because)
7.My father got upset because i repeatedly left on the lights i was not using (so)
8.The contaminated drinking water caused the outbreak of cholera in the village (due to)
9. Human activity is to blame for many forms of pollution on earth (result in)