Answer:
1/8 of a chance to flip 3 coins and get that exact combination in that order
Explanation:
a coin has 2 sides, heads and tails, with an equal chance to land on each of them. 1/2 chance to get tails on the first flip x 1/2 chance to get heads on the second flip x 1/2 chance to get tails on the third flip. 1/2 x 1/2 x 1/2 = 1/8.