The sum of two numbers is 18. there difference is eight. if the numbers are x and y, write a system of equations to describe their sum and their difference.

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

At the beginning of year 1, carlos invests $600 at an annual compound interest rate of 4%. he makes no deposits to or withdrawals from the account. which explicit formula can be used to find the account's balance at the beginning of year 5? what is, the balance?

Micheal is 4 times as old as brandon and is also 27 years older than brandon. how old is micheal