jmc

First, we wish to determine what percentage of the tons of apples are used for apple juice. After $20\%$ is mixed with other products, $80\%$ remains. Half of this is used for apple juice; therefore, $40\%$ of the tons of apples is used for apple juice. To calculate $40\%$ of $5.5$ million tons, we find $10\%$ and then multiply by four. $10\%=0.55$, and $0.55\cdot 4=2.2$. Thus, $\boxed{2.2}$ million tons are used for apple juice.