conversations.from: human
conversations.value: Rihanna has $50 to go to the supermarket. Rihanna bought 6 mangoes and 6 cartons of apple juice. Each mango cost $3 and each carton of apple juice cost $3. How much money does Rihanna have left?
  Work out the solution step by step.
conversations.from: assistant
conversations.value: The cost of the mangoes is 6 mangoes × $3/mango = $18.
  The cost of the apple juice is 6 cartons × $3/carton = $18.
  Find the total cost of the groceries which is $18 + $18 = $36.
  Rihanna has $50 − $36 = $14 left.