"The ratio of the note an octave and a fifth to the root is 3:1 because the fifth an octave higher is twice the frequency of the original fifth, and 3/2 (the fifth) x 2 (the octave) is 3" (Benner). The ratio is 3:1.
In terms of the note-to-note ratios, a chord made by a fifth and a major third is more consonant (this is a hard term to describe in words - it's sort of like dominance in a sound verses submission) than a minor triad which is made of a fifth and a minor third. Because of the increased consonance between major versus minor triads, they seem more fulfilling to our emotions.