Physical Fitness Index = (Duration of exercise in seconds x 100)/(5.5 x Pulse count between 1-1.5 minutes)
Duration of exercise for 12-year old boy = 3 minutes
Pulse count for 1 to 1.5 minutes = 54
So, Physical Fitness Index = (3 x 60 x 100)/(5.5 x 54) = 18000/297 = 60.6
So, by looking at the norms of Harvard Step Test, the 12 year old boy physical condition is under the category of low average.