Tina lives 30 miles away from her work, and she normally drives at 45 miles per hour. If she wants to get to work 10 minutes earlier, how fast should she drive to work, in miles per hour?
+2666 At her average speed, she gets to work in \({30 \over 45} = {2 \over 3}\) of an hour or 40 minutes.
To get to work 10 minutes earlier, she needs to go 30 miles in 30 minutes, or a speed of \({30 \text{ miles} \over 0.5 \text{ hours}} = \color{brown}\boxed{60 \text{ mph}}\)
