EXAMPLE $12$

You have a furnace to burn a coal slurry containing $70\%$ coal And $30\%$ water by mass. However, a supplier prepares a $45\%$ Concentrated slurry which you must render usable for your furnace. You are receiving $5000l\frac{b}{h}$ of this slurry and you wish to concentrate it from $45\%$ to $70\%$ by using an evaporator. Find the amount of water to be evaporated.