A curious trip on the river – The big puzzles

A curious trip on the river. Emma la pasticciera, a well-known fan of mathematical puzzles and problems of logic after a long study, decided to select the most beautiful logical-mathematical games of all time by proposing their solutions separately. These are questions and riddles that require both logical and creative skills to be solved. The perfect mathematical puzzle must propose a simple situation to explain and a solution just as easy to understand but very complicated to find, often at the limit of the impossible for an average mind.

In this page we present The curious trip on the river a nice mathematical problem that can be solved according to two models: one quite complex and one clamorosamente easy!


That Saturday afternoon Emma is on the boat of Giuseppe, professor of Physics at the University who she met a few weeks before at a birthday party of her friend. Giuseppe is an experienced captain and Emma is enjoying the view. It’s very curious to see Rome going up the Tiber. Changing point of view everything seems different, almost like another city.

Emma looks with admiration at the safety with which Giuseppe manages the boat and everything proceeds for the best when passing under a bridge the waves make the boat shake more than normal and the life preserver resting on the edge because of the jolt ends up in the sea without anyone of the two notice. After exactly twenty minutes of constant gait, Giuseppe notices the lack and immediately goes back at the same speed as the water.

The boat reaches the life preserver one kilometer downstream of the bridge.

Can you determine the speed of the river water? 

Can you do it without using equations?

(Bottom page the solution)

Musical interlude

Namibia… where the Nature is the king


Giuletta – A Music Video for the Universal Children’s Day


Trees – Our Future

Gli alberi


Come and discover the magical musical world of Lorenzo Pescini!

ART523 – All rights reserved- Pescini.com