Haretown and Tortoiseville are 30 miles apart. A hare travels at 7 miles per hour from Haretown to Tortoiseville, while a tortoise travels at 3 miles per hour from Tortoiseville to Haretown. If both set out at the same time, how many miles will the hare have to travel before meeting the tortoise en route?

The hare and tortoise travel toward each other, so their combined speed is 7 + 3 = 10 mph. To cover 30 miles, they need 30/10 = 3 hours. In 3 hours, the hare travels 7 × 3 = 21 miles before meeting the tortoise. Option A (22 miles) and Option C (20 miles) are incorrect calculations, while Option D doesn't match the mathematical result.