MathDB

The distance between cities

A

and

B

30

km. Three tourists went from

A

B

. The three of them have two bicycles: a racing bike, on which each of them rides at a speed of

30

km/h, and a tourist bike, on which they can travel at a speed of

20

km/h. Each of them can walk at a speed of

6

km/h. Any bicycle can be left on the road, where it will lie until another tourist can use it. Tourists want to get to

B

in the shortest time possible, with the end time of the trip corresponding to the moment the last of them arrives at

B

. What is this shortest time?

Problem Statement