Students at Flemington College were surveyed to determine the type of tea they drink: black
(B) or green (G). Students who don't drink tea did not participate in the survey. The number of students who drink only black tea was three times more than the number of students who drink only green tea. 20 students indicated drinking both black and green
tea. Let a be the number of students who drink only black tea. (a) Write down an expression, in term of x, for the number of students who drink only
green tea.
(b) Complete the Venn diagram below using the above information.