An eighth note triplet is a group of three evenly spaced notes played within one beat. Eighth note triplets are indicated by three eighth notes grouped together with the numeral 3 above or below them. Each part of the triplet is worth a third of a beat. Triplets are easy to understand once you have heard them played. Listen to example 73.0 on the CD to hear the effect of triplets.
Playing a triplet on each note of a scale is a good way to develop your alternate picking technique, because each note starts with an opposite stroke to the last one. This will help you become equally comfortable playing any note with either a downstroke or an upstroke.