Question

Distanta dintre 2 orase a fost parcursa in 3 etape.In peima etapa s-a parcurs 35% , in a doua etapa 60% din rest iar in a treia etapa au fost parcursi ultimii 7,8 km.Aflati distanta dintre orase

Answer 1

d=distanta;a=prima zi;b=a doua zi ;c=a 3a zi
a=35%*d=>R=65%*d
b=60%*R=>c=40%*R
c=7,8km
2R/5=78/10
4R=78
R=78/4=39/2
65/100 *d=39/2
65d/100=39/2
65d=39*50. l :5
13d=39*10 l:13
d=3*10
d=30 km

Answer 2

1.
35x/100=7x/20
x-7x/20=20x/20-7x/20=13x/20

2.
60/100*13x/20=3/5*13/20=39x/100


3.
7x/20+39x/100+7,8= x
100x-35x-39=780
26x=780
x=30 km