conversations.from: human
conversations.value: Can you explain how to solve this math problem: Alexa and Emily open up a lemonade stand in the front yard. They spent $10 for lemons, $5 for sugar and $3 for cups.  The lemonade is $4 a cup.  They sell a total of 21 cups.  How much profit did Alexa and Emily make after paying off expenses?
conversations.from: assistant
conversations.value: Alexa and Emily spend a total of $10 + $5 + $3 = $18.
  They make a total of $4 x 21 = $84.
  They make a profit of $84 - $18 = $66.