question: How many field goals measured between 30-yards and 40-yards in length?
#1 return field goals 
#2 return lengths of #1 
#3 return #1 where #2 is at least 30-yards 
#4 return #1 where #2 is at most 40-yards 
#5 return #1 in  both #3 and  #4 
#6 return number of  #5