MathDB

Anna and Lisa go for a bike ride. Anna's bike breaks down

30

kilometers before their final destination. The two decide to complete the ride with Lisa's bike as follows: At the beginning, Anna is riding a bike and Lisa leaves. At some point, Anna gets off the bike, parks it on the side of the road and continues by foot. When Lisa gets to the bike, she takes it and rides until she catches up with Anna. After that, they repeat the same procedure. We don't know how many times the procedure is repeated, but they arrive at the final goal at the same time. Anna walks at a speed of

4

km/h and cycles at a speed of

15

km/h. Lisa walks at

5

km/h and cycles with

20

km/h. How long does it take them to cover the last

30

km of the road? (Neglect the time it takes to park, lock, unlock the bike, etc.)

Problem Statement