Question

Ion parcurge cu autocarul un drum in trei zile.In prima zi a parcurs 20% din drum,in a doua zi 30% din rest si in a treia zi ultimii 560 de kilometri din drum.Determinati lungimea drumului parcurs in cele trei zile

Answer 1

X-lungime drum
Prima zi- 20/100xX=X/5
X-X/5=5X-X/5=4X/5(restul)

A doua zi- 30/100x4X/5=6X/25
A treia zi- 560 km
Acum aduni ce ti a dat in cele 3 zile
X=X/5 + 6X/25 + 560=5X + 6X+560x25/25=11X+560x25/25
25X=11X+560x25
25X-11X=14000
14X=14000
X=1000km

Answer 2

x-tot drumul

x-20/100 ·x=-km a parcurs prima zi 
30/100· 20x/100-km a parcurs in a doua zi (rest=total-prima zi)
rest=x-80x/100(aduci la acelasi numitor,adica 100)=(100x-80x )/100=20x/100
560km-a parcurs in treia zi

x-20/100 ·x=(100x-20x)/100=80x/100-prima zi


80x/100+3/10 · 2x/10+560=x
80x+6x+56000=100x
86x-100x=-56000
-14x=-56000/(-1)
14x=56000
x=56000/14
x=4000-tot drumul

4000-20/100 ·4000=4000-800=3200km-parcursi in prima zi
4000-3200=800km-au ramas
30/100 ·800=240km-au fost parcursi in a doua zi 
560km-a treia zi

V:3200+240+560=4000km-tot drumul

Sper ca te-am ajutat..