Suppose thirty-six students signed up for class orientation sessions. If exactly twenty-two of them signed up for chemistry and exactly eighteen of them signed up for English. How many of them signed...

Suppose thirty-six students signed up for class orientation sessions. If exactly twenty-two of them signed up for chemistry and exactly eighteen of them signed up for English. How many of them signed up for both chemistry and english? How many of them signed up for chemistry? How many of them signed up for english only? Polya's problem solving