Question 143
Container $A$ contained a mixture that is $40\%$ acid, while container $B$ contained a mixture that is $60\%$ acid. A chemist took some amount from each container, and mixed them. To produce 100 liters of mixture that is $17\%$ acid, she needed to pour 70 liters of pure water to the mixture she got from containers $A$ and $B$. How many liters did she take from container $A$ ?