SOLUTION STEPS (Set 7):
  1. Write all numbers with 3 decimal places: 3.115, 3.511, 3.500, 3.150.
  2. Compare tenths: 3.511 and 3.500 have tenths 5 (largest). Compare hundredths: 1 > 0.
  3. So 3.511 is the greatest number. Match the second option.