One coin is chosen at random, so each has probability $\tfrac{1}{2}$ of being selected.

Let $P(H)$ = probability of getting head.

Using the law of total probability:

$P(H) = \tfrac{1}{2} \times 0.99 + \tfrac{1}{2} \times 0.01 $$ = \tfrac{1}{2}(1.00) = 0.50$

✅ Final Answer: ${0.5}$