1. A friend of yours auditioned to Caraga Got Talent Online. Of the five songs he submitted, he is required to sing any three songs. How many ways can he make his choices?
2. Caraga Got Talent Online has declared 10 lucky singers who passed the online audition and are qualified for the semi-final round. Suppose the first and last singers were already determined by the judges. How many possible ways can the singers be arranged for the online showdown?
3. Suppose the Semi-Final Round changes its format from showdown to face-off and the pre-determined singers were chosen to be one of the matches. How many face-off rounds will there be?​