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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?

 Jul 18, 2020
 #1
avatar+37146 
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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

 Jul 18, 2020
edited by ElectricPavlov  Jul 18, 2020
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wait its right thank you!!

 Jul 18, 2020
edited by Creampuff  Jul 18, 2020
 #3
avatar+37146 
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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 !  

ElectricPavlov  Jul 18, 2020

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