Question

In a survey of 25 students it was found that 15 had taken maths 12 had taken physics and 16 had taken chemistry ,5 had taken maths and chemistry,9 had taken maths and physics and 4 had taken physics and chemistry, and 3 had taken all the 3 subjects.Find the no of students who had not taken any of the 3 subjects

Answer 1

Its impossible because according to set theorems I am getting negative value so please check the question .