Răspuns :

Aledan12id

Salut!

a/b=2/5 ⇔ 5a=2b ⇔ a=2b/5

a+b+30=100

2b/5 +b=100-30

2b/5 + 5b/5 = 70

7b/5=70

b=70x5/7

b=10x5

b=50

a=70-50

a=20

Succes!

Răspuns:

Explicație pas cu pas:

a/b = 2/5

a = 2b/5

a + b + 30 = 100

a + b = 100 - 30 = 70

2b/5 + b = 70

2b/5 + 5b/5 = 70

7b/5 = 70

b = 5*70/7 = 50

a = 2*50/5 = 20

___________

verificare

20/50 = 2/5

20 + 50 + 30 = 100

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