4. Four years ago, Melody was one fourth as old as her sister was then. In six years, Melody will be half as old as her sister will be then. Find their ages now.
5. The sum of the digits of a fwo-digit number is 12. The value of the number is 6 less than 5 times the units digit. Find the number.
6. Hannah likes to spend her free time hanging out at the airport. She likes to run on the walkways. While running with the walkway, she can cover 48 feet in 3 seconds. While running against the walkway, she can cover 24 feet in 2 seconds. Find Hannah's rate (in feet per second) if the walkway stopped moving.