# 第四天
# 变量和命名
# 在编程中，变量只不过是用来指代某个东西的名字

# 汽车
cars = 100
# 车内空间
space_in_a_car = 4.0
# 驾驶员
drivers = 30
# 乘客
passengers = 90

cars_not_driven = cars - drivers
cars_driven = drivers
carpool_capacity = cars_driven * space_in_a_car
average_passengers_per_car = passengers / cars_driven

print("There are", cars, "cars available.")
print("There are only", drivers, "drivers available.")
print("There will be", cars_not_driven, "empty cars today.")
print("We can transport", carpool_capacity, "people today.")
print("We have", passengers, "to carpool today.")
print("We need to put about", average_passengers_per_car, "in each car.")