Răspuns:
Explicație pas cu pas:
x/5 = y/3 = z/7 = k
x = 5k
y = 3k
z = 7k
x - y + 2z = 32
5k - 3k + 14k = 32
16k = 32
k = 32 : 16 = 2
x = 5*2 = 10
y = 3*2 = 6
z = 7*2 = 14
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4.
6 muncitori..................10 zile
1 muncitor .................6*10 = 60 zile
4 muncitori.....................60 : 4 = 15 zile
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6.
n*80/100 = 100
n = 100*100/80 = 125
