Question

Si a + b + c = 40, a -b = 20 y a -c = 30.
Calcular "a"

Answer 1

a - b = 20 -------> b = a - 20

a - c = 30 ------> c = a - 30

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a + b + c = 40

a + (a-20) + (a-30) = 40

(a+a+a) - 20 - 30 = 40

3a - 50 = 40

3a = 40 +50

3a = 90

a = 90/3

a = 30

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eso es todo , espero se entienda xD

SALUDOS!!