+1678 Ruth has a beaker containing a solution of $800$ mL of acid and $200$ mL of water. She thinks the solution is a little strong, so she drains $150$ mL from the beaker, adds $150$ mL of water, and stirs the solution. Ruth thinks the solution is still too strong, so again she drains $250$ mL from the beaker, and adds $250$ mL of water. How many mL of water are now in the beaker?
+22 800mL acid + 200mL water = 1000mL of total liquid.
Draining 150mL of total liquid
150/1000 = 15%, which means 15% of the water and 15% of the acid will be drained.
0.85* 800 = 680mL acid
0.85* 200 = 170mL water
= 680mL acid and 170mL water
Adding 150mL water
170 + 150 = 320mL water
So there would be 680mL acid and 320mL water.
Draining 250mL of total liquid
680 + 320 = 1000mL total liquid
250/1000 = 25%, which means 25% of the water and 25% of the acid will be drained.
0.75*680 = 510mL acid
0.75*320 = 240mL water
Adding 250mL water
240 + 250 = 490mL water
So your final answer is 490mL water.
