In a tree, 2/5 of the birds are robins while the rest are bluejays. If 1/3 of the robins are female and 2/3 of the bluejays are female, what fraction of the birds in the tree are male?  Pick
A) 3 / 5	B) 4 / 15	C) 7 / 15	D) 8 / 15	E) 17 / 30

Rationale: the fraction of birds that are male robins is ( 2 / 3 ) ( 2 / 5 ) = 4 / 15 . the fraction of birds that are male bluejays is ( 1 / 3 ) ( 3 / 5 ) = 1 / 5 . the total fraction of male birds is 4 / 15 + 1 / 5 = 7 / 15 . the answer is c .
Answer: C