Joseph mixes $x$ milliliters $(\text{mL})$ of a cranberry drink containing $10\%$ real juice with $200\,\text {mL}$ of a cranberry drink containing $70\%$ real juice to make $y\,\text {mL}$ of a $50\%$ cranberry juice mix. Which of the following systems of equations could be used to determine how much of the cranberry drink containing $10\%$ juice Joseph put into the mixture? [[☃ radio 1]]