Answer:
Each one has two possibilites, so the total is 2*2*2*2 = 16
Step-by-step explanation:
TTTT
TTTH
TTHT
TTHH
THTT
THTH
THHT
THHH
HTTT
HTTH
HTHT
HTHH
HHTT
HHTH
HHHT
HHHH
If you eliminate the duplicates, ie, the coins are identical, you get 4
TTTT
TTTH
TTHH
THHH
HHHH
