The space shuttle can travel at approximately 410,000 miles per day. If the shuttle could travel to Mars, and Mars was 140,000,000 miles away, how many days would it take the shuttle to travel to Mars? Express the result in decimal form.

In 2010, the U.S. population was 309.9 million and there were 128,900,000 American Facebook accounts. Approximately one-third of all Facebook accounts are owned by someone under the age of 25. How many Facebook users in 2010 were under 25? Write your answer in scientific notation, with the mantissa rounded to 1 decimal place.

Suppose we lined up all the people in the world (about 7.8 billion people). Assume that each person occupied 12 inches of the line. How many times around Earth would they reach? (Earth has a circumference of about 25000 miles.) (Use decimal notation. Give your answer to one decimal place.) number of times wrapped around the earth:

Geographers find that the length of a river varies with the 0.6 power of the river basin. The Rio Grande is 3034kilometers long, and the basin is 500,000 square kilometers. Find the particular equation and use it to predict the riverbasin of the Nile (to the nearest hundred‐thousand), which at 6700 kilometers is the longest river in the world.