Effect across kinds of day

Calm days are $70\%$ of all days and volatile days are $30\%$. On calm days strategy $A$ hits its target $60\%$ of the time and strategy $B$ hits it $55\%$. On volatile days $A$ hits $40\%$ and $B$ hits $50\%$. Within each kind of day a coin decides which strategy runs. What is the average effect of running $A$ instead of $B$ on the hit rate over all days? Give a number of percentage points, negative if $A$ is worse.

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