How do you correctly write an ordered pair? (y, x) or (x, y)

Determine the number of girls in a math class with 87 boys if there are 25 girls for every 75 boys

What is the sum of these mixed numbers 4 2/3+ 3 1/9

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?