total number of racers = 220
Racers who did not complete the race = Racers who gave up + who were
disqualified
= 12 + 5
= 17
percentage did not complete marathon
who did not complete the race
x 100
total number of racers
required percentage
17
220
x 100
required percentage = 0.07727272727 x100
required percentage = 7.72727272 %
required percentage ~ 7.73 %
Answer is: 7.73%