Pedro's mother picks him up every day from school with the car.
The mother always leaves the house with the car at the same time, picks it up at the door of the school at 5:30 and returns home on the same road, using the same time both on the way out and on the way back, So they always arrive at the same time home.
One day, the classes ended earlier, Pedro left school at 4:58 and began to walk towards his home on the same route as when he was driving. His mother followed the usual routine, but this time he picked him up on the road, returning home together. They arrived 4 minutes earlier than usual.
How long was Pedro walking?
Exactly 30 minutes. If they arrived 4 minutes earlier than usual, it means that the mother saved 2 minutes one way and two around the corner so they met at 5:28 instead of 5:30. If he started walking at 4:48, he had been walking for 30 minutes.