Răspuns :
Răspuns:
x=60y/100
x=3y/5=>5x=3y=>x,y invers prop cu 3 si 5
2x+5y=310
5(2x+5y)=5·310
10x+25y=1550
5x=3y I·2
10x=6y
6y+25y=1550
31y=1550=>y=1550:31=>y=50
x=60y/100=>x=50·60:100=30
Răspuns:
Explicație pas cu pas:
x = 60% din y ⇒ x = 6y/10 = 3y/5
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[ x; y] i.p. [ 5; 3]
⇒ 5 x = 3 y = k ⇒ x = k/5 si y = k/3
x = 3 y/5 = 3 × k/3 × ( 1/5 ) = k/5
_________________________
b)
2 x + 5 y = 310
2 × k/5 + 5 × k/3 = 310 l × 15
6 k + 25 k = 310 × 15
31 k = 310 × 15 l : 31
k = 150
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x = 150/5 ⇒ x = 30
y = 150 /3 ⇒ y = 50