Tally Lake is 11.25 miles long. Mary starts at one end and kayaks toward the other end, paddling at a constant rate of 2.5 miles per hour. At the same time, Ann starts out from the opposite end and paddles towards Mary at a constant rate of 2 miles per hour. How long will it take for the girls to meet?
Their closing speed is 2.5 + 2 = 4.5 m/hr
11.25 m / 4.5 m/hr = 2.5 hr