Question

La o benzinarie au sosit 3 cisterne cu combustibil, aducand in total 1000 l. Primele doua cisterne au adus 640 l iar ultimile doua 800 l. Cati l a adus fiecare cisterna?

Answer 1

a+b+c= 1000l
a+b=640=> a=640-b
b+c=800=> c=800-b
640-b+b+800-b=1000
1440-1000=b+b-b
440=b
a=640 - 440
a=200
c=800-440
c=360

Answer 2

a + b + c = 1000
a + b = 640
b + c = 800
640 + c = 1000
c = 1000 - 640
c = 360 l a treia cisterna
a + 800 = 1000
a = 1000 - 800
a = 200 l prima cisterna
b = 1000 - 200 - 360
b = 440 l a doua cisterna