2)
a)
x=lungimea drumului
Prima zi: x/10+2
Rest 1: x-(x/10+2)=x-(x/10+20/10)=10x/10-[(x+20)/10]=[10x-(x+20)]/10=
(9x-20)/10
A doua zi: (2/5)*[(9x-20)/10]+5=(9x-20)/25+125/25=(9x+105)/25
Rest 2: (9x-20)/10-(9x+105)/25=(45x-100)/50-(18x+210)/50=
[(45x-100)-(18x+210)]/50=(27x-310)/50
A treia zi: 10km
(27x-310)/50=10
27x-310=10*50
27x=500+310
27x=810
x=810:27
x=30km
b)
In a doua zi a parcurs: (30*9+105)/25=375/25=15km
Regula de 3 simpla:
30km.....100%
15km....x%
x=15*100/30=50%
