conversations.from: human
conversations.value: Explain how to solve this math problem: In a class of 30 students, the teacher polls the students on their favorite subject. 1/5 of the students like Math, and 1/3 like English. 1/7 of the remaining students like Science. The rest don’t have a favorite subject. How many students don’t have a favorite subject?
conversations.from: assistant
conversations.value: 30 x 1/5 = 6 students like Math.
  30 x 1/3 = 10 students like English.
  So, 6 + 10 = 16 students like either Math or English.
  Thus, 30 - 16 = 14 students neither like Math nor English.
  Since 1/7 of the remaining like Science, therefore 14 x 1/7 = 2 students like Science.
  Hence, 14 - 2 = 12 students neither likes the 3 subjects.