To solve this, we need to use the z statistic. The formula for z score is:
 z = (x – u) / s
 where x is sample value = less than 90, u is the sample mean = 90.6, s is the standard deviation = 17.2
  
 z = (90 – 90.6) / 17.2
 z = -0.035
  
 From the standard distribution tables:
 P (z = -0.035) = 0.4860
  
 Therefore there is about 48.60 % chance that it will be less than 90 pounds