If a, b, c, d, e, f are nonnegative real numbers satisfying a \plus{} b \plus{} c \plus{} d \plus{} e \plus{} f \equal{} 1 and ace \plus{} bdf \geq \frac {1}{108}, then prove that
abc \plus{} bcd \plus{} cde \plus{} de f \plus{} efa \plus{} fab \leq \frac {1}{36}
inequalitiesinequalities solved