Question

Help me pls..AJUTOR....

Answer 1

a)

12 h=12*60=720 min

3/5 h=3/5*60=36 min

2460 sec=2460:60=41 min

b)

x-numarul de bacnote de 5 lei

y-numarul de bacnote de 10 lei

stim ca x+y=100 si 5*x+10*y=800, aceste ecuatii formand un sistem.  Daca inmultim prima ecuatia cu -5 obtinem -5x-5y=-500 si 5x+10y=800. Daca le adunam obitnem 5y=300 adica y=60 si x=100-60=40

c)

Notam cu x cantitatea de lichid initial si obtinem

$x-x*\frac{1}{3}=150\\\frac{2}{3}*x=150\\x=\frac{150*3}{2}=225 l$

$capacitate*\frac{3}{4}=225\\capacitate=\frac{4*225}{3}=300l$