Office Riddle 19

Q: An old man dies, leaving behind two sons. In his will, he orders his sons to race with their horses, and the one with the slower horse will receive his inheritance. The two sons race, but since they’re both holding their horses back, they go to a wise man and ask him what they should do. After that, the brothers race again — this time at full speed. What did the wise man tell them?

A: To switch horses