Question

Se toarnă 90 de litri de apa in 13 sticle :unele au capacitatea de 2 litri iar altele de 10 . Cate sticle scunde de fiecare fel . Repede va rog ,daca puteti sa-mi Spune-ți cum se fac nu le inteleg

Answer 1

x-nr. sticle de 10 l
y-nr. sticle de 2 l
10·x+2·y=90
x+y=13⇒x=13-y
10(13-y)+2y=90⇔130-10y+2y=90⇔130-90=10y-2y⇔40=8y⇔y=40:8⇔y=5⇒5 sticle de 2 l
x=13-y=13-5=8⇒8 sticle de 10 l

Verificare
10·8+2·5=80+10=90l
8+5=13