Answer: 1/4
Step-by-step explanation: someone already said this, but I would like to provide a more detailed explanation, although there isn't too much to explain, so, to the find ratio of 2 things happening one after another, you want to multiply the ratios together, so the ratio of heads in the first one and tails in the second one is 1/2, and 1/2, so you multiply 1/2*1/2 and you get 1/4