Question

a+b=60, b+c=78,c+a=306 atunci(a+d+c):3

Answer 1

a + b      = 60

     b + c = 78

a +      c  = 306

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2 × a + 2 × b + 2 × c = 60 + 78 + 306

2 × ( a + b + c ) = 444

a + b + c = 444 : 2

a + b + c = 222 → suma celor trei numere

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( a + b + c ) : 3 = 222 : 3 = 74