Kolya and his sister Masha went to visit someone. After walking a quarter of the way, Kolya remembered that they had forgotten the gift at home and turned back, while Masha continued on. Masha arrived at the visit 20 minutes after leaving the house. How many minutes later did Kolya arrive at the visit, given that they walked at the same speed the whole time?
Kolya walked an "extra" half of the distance. This means the delay time is equal to half of the time spent on the entire journey, which is 10 minutes.

## Answer

10 minutes.