[
  "Subtract the amount used from the amount she had. Convert both mixed numbers to fractions with a common denominator. LCM of 5 and 4 is 20.",
  "3 2/5 = 17/5 = 68/20. 1 1/4 = 5/4 = 25/20. 68/20 - 25/20 = 43/20.",
  "43/20 = 2 3/20 kg of rice left. Answer: 2 3/20 (option B)."
]