Responder:
Número total de bolas = 245/23
Explicación paso a paso:
Dado que:
Bolas blancas = 1/5
Bolas negras = 1/7
Bolas rojas = 7
Sea el número total de bolas = x
Bolas blancas = 1 / 5x
Bolas negras = 1 / 7x
Por tanto, total;
(x / 5 + x / 7 + 7) = x
((7x + 5x) / 35) +7 = x
(12x / 35) + 7 = x
7 = x - 12x / 35
7 = (35x - 12x) / 35
7 = 23 veces / 35
245 = 23x
x = 245/23
Answer: 15/24...i'm not sure though *scratches head*
Lets first numbers is x, second is (x+2), third is x+4
sum is x+(x+2)+(x+4)=87
3x+6=87
3x=81
x=27
Answer: smallest number is 27