Notam cu a numarul de km
in prima zi : a/3
in a doua zi : 2/5*(a-a/3) = 2/5 * 2a/3 = 4a/15
in a treia zi: 3/4* (a-a/3-4a/15) = 3/4* (6a/15) = 18a/60= 3a/10
a/3+4a/15+3a/10+6=a
10a+8a+9a+180=30a
180=3a => a= 60 km
Verificare:
in prima zi: 60/3=20
in a doua zi: 2/5 *40 = 16
in a treia zi: 3/4 * 24 = 18
20+16+18+6 = 60