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? Give me reasons, before answering the question
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. So the final answer is 12.