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 100 mL from the beaker, adds 100 mL of water, and stirs the solution. Ruth thinks the solution is still too strong, so again she drains 100 mL from the beaker, and adds 100 mL of water. How many mL of water are now in the beaker?
When Ruth originally drains water 200 out of 1000 is water 2/10
2/10 of 100 drained is 20 which leaves 180 ml
add 100 ml = 280 ml of water now in beaker of 1000 ml 280/1000 = 7/25 is water
draining 100 removes 7/25 x 100 = 28
280 - 28 = 252 ml
then she adds another 100 ml water 252 + 100 = 352 ml water in final solution
Sorry.....when hit 'post answer' I saw an error that I quickly edited....but you must have originally read the first version before I got my quick edit in there ! Usually I highlight edits, but this was a quick one.....but YOU were quicker !