Răspuns :
a + b = 2 400 litri
a - 200 = b + 200
a = b + 400
b + 400 + b = 2 400
2 × b = 2 400 - 400
2 × b = 2 000 |:2
b = 1000 litri (in a 2-a cisterna)
a = 1000 + 400 = 1 400 litri (in prima cisterna)
Verificare:
1400 + 1000 = 2 400
grafic:
a |________|+400
b |________|
2400 - 400 = 2000
2000 : 2 = 1000
a = 1000 + 400 = 1400
b = 1000
a - 200 = b + 200
a = b + 400
b + 400 + b = 2 400
2 × b = 2 400 - 400
2 × b = 2 000 |:2
b = 1000 litri (in a 2-a cisterna)
a = 1000 + 400 = 1 400 litri (in prima cisterna)
Verificare:
1400 + 1000 = 2 400
grafic:
a |________|+400
b |________|
2400 - 400 = 2000
2000 : 2 = 1000
a = 1000 + 400 = 1400
b = 1000
punem Pb in ecuații
x,y cele două cisterne
x+y=2400l. (1)
x-200l=y+200l
x-y=400l. (2)
adunând (1)+(2)
2x. /=2800l
x=1400l
înlocuind in (2)
1400-y=400
y=1000l
proba
1400l+1000l=2400l
1400-200=1000+200
1200l=1200l
x,y cele două cisterne
x+y=2400l. (1)
x-200l=y+200l
x-y=400l. (2)
adunând (1)+(2)
2x. /=2800l
x=1400l
înlocuind in (2)
1400-y=400
y=1000l
proba
1400l+1000l=2400l
1400-200=1000+200
1200l=1200l