How does the geographical position of the USA explain the following facts about people’s lives? Find the reasons in the description of the USA in exercise 2 on page 5.

When it’s 9 am in Los Angeles, it’s already midday in New York due to the fact that people live within four time zones.
Millions of Americans participate in water sports, such as swimming, surfing, fishing, sailing and water skiing because 3-4 of the country are washed by the ocean.
Fresh grapefruits, oranges, lemons, melons, cherries and peaches are not imported. Low-cost high-quality fruits, juices and vegetables are available any time of the year thanks to the fact that in southern parts of the country have warm temperatures all year round.
A fast railroad train, travelling 96 kilometres an hour, takes more than 45 hours to cross the country, because the USA cover 4500 kilometres.
Americans who prefer various landscapes can easily spend interesting vacations within the country due to the fact that landscape varies very much.

Меди 20%цинка 80%20кг - 80%20%=80%/420кг/4=5кг5кг=20% -> масса меди = 5кг