There are 6 students and 3 dormitory rooms which can hold 2 students each. In how many ways can you assign students into these rooms?

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.

The price of a car has been reduced from $19,000 to $11,590. what is the percentage decrease of the price of the car?

Use mathematical induction to prove the statement is true for all positive integers n, or show why it is false. 1^2 + 4^2 + 7^2 + + (3n - 2)^2 = [n(6n^2-3n-1)/2]