Ben and Leonidas are twins who are both in Hufflepuff. Ben is ready first, so he leaves the common room and starts flying to class at an average
speed of 20 km per hour. Half an hour later, Leonidas leaves the common
room on his Firebolt 3000 sports broom and follows the same route,
traveling at an average speed of 70 km per hour. How many minutes will it
take Leonidas to catch up with Ben, starting from when Leonidas leaves
the house?
11 minutes
O 12 minutes
17 minutes
O 20 minutes