Fresh Grapes contain 90% water by wt. Dried grapesn 20% water by %age. What will b wt of dried grapes w?

Question

Fresh Grapes contain 90% water by wt. Dried grapes contain 20% water by %age. What will b wt of dried grapes when we begin with 20 kg fresh grapes?

plz explain the ans in detail

thank u

Answer 1

Fresh grapes contain 90% of their wt as water, alrite. so wt of water in fresh 20 kg grape would be:

          

                  ( 20/100) * 90 = 18 kg.

So the dry wt of grapes is 2 kg. This dry wt is not going to go watever you do with it.

now what would be the wt of dried grapes which contain 20% of water by wt?

  

suppose the total wt of dry grapes is W...

                        

                       W= dry weight of grapes + 20% of W

                => W  = 2kg + (W/100) * 20

            

                => W  =2 kg + W/5

                    

               => 2kg = W - W/5 = (5W - W)/5

              

               => 4W/5 = 2kg

                  

               => W =(2*5)/4 =5/2 kg i.e. 2.5 kg

now the waight of water in dry grapes is 20 % of total weight which is 2.5 kg, so the wt of water would be:

                  wt of water= 20% of W= (W/100) * 20 = W/5 = 2.5/5 =(5/2)/5 = 5/ (2*5) = 5/10 = 0.5 kg

so the wt of water in dry grapes would be 0.5 kg...

I know this will help...