Explanation:
1 (b) ( boy, boy), (boy,girl), ( girl,boy ), ( girl, girl )
(c) 4
(d) 2/4 = 1/2
(e) 1/4
2 (a) (1,head), (1,tail), (2,head), (2,tail), (3,head), (3,tail), (4,head), (4,tail)
(b) (A,1) (A,2), (A,3), (B,1), (B,2), (B,3), (C,1), (C,2),
(C,3)