Concept: The question tests on basic reasoning skills of Arithmetic


St(1):- a/b  <0.818
   You "know" that you can convert 9/11 into a decimal and "decide/judge" if a/b is less or more than that  based on the information that a/b is less  than 0.818.You do not need to calculate.) Sufficient

S(2):- b/a >1.223
      =>a/b < .817  (Taking reciprocal. You "know" you can get the reciprocal and hence you have to decide that the         If a and b are positive integers, value of 0.817 "can" be calculated and you do not need to calculate it actually)

       Hence now when you know that a/b <0.817 ,you can decide and answer if it is less than 9/11. (Sufficient)