Why is it called the 21" century when the year is 2002?

Brent works part-time at a clothing store. he earns an hourly wage of $15. if he needs to earn more than $45 in a day and works for x hours a day, which inequality represents this situation? a. 15x > 45 b. 15x < 60 c. x > 60 d. 15x < 45 e. x < 60

According to modern science, earth is about 4.5 billion years old and written human history extends back about 10,000 years. suppose the entire history of earth is represented with a 10-meter-long timeline, with the birth of earth on one end and today at the other end.

Could someone me with this question i’ve been stuck on it for 20 minutes