1. the first time i have made mooncakes fot the Mid-Autumn Festival.
2. desire to expolre the hidden gems of the city that most tourists miss.
3. he had a big house to get a pet.
x là V ca nô (km/h, x>0)
x >= 40
V xuôi dòng: x + 6 >= 46
S dòng sông: (2+30/60) x (x+6) >= 115