In our solar system six of the eight planets have moons what percentage of the planets have moons

For how answer my question this will be the last question can you answer in math subject

If you had $1,900,000, how many days would it take you to spend all if you spent $1 a second. (there are 86,400 seconds in a day)

You just purchased two coins at a price of $670 each. because one of the coins is more collectible, you believe that its value will increase at a rate of 7.1 percent per year, while you believe the second coin will only increase at 6.5 percent per year. if you are correct, how much more will the first coin be worth in 15 years?