Question

valores desconhecidos a/20= b/7= c/3 é a-b+c=

Answer 1

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$a-b+c=80~~~~~e~~~~ \frac{a}{20} = \frac{b}{7} = \frac{c}{3} \\ \\ \frac{a-b+c}{20-7+3} = \frac{80}{16} =5 \\ \\ \frac{a}{20} =5~~~~~~~~ \frac{b}{7} =5~~~~~~~~ \frac{c}{3} =5 \\ \\ a=100~~~~~~b=35~~~~~~~~c=15$