we have to add 100 cc of 11% saline solution to the 100 cc of 21% saline solution to get a slution of 16%.
we will have a 200 cc solution containing 11 + 21 = 32 cc of saline. that means that in a solution of
200/2=100 cc , we will have. 32/2=16 cc of saline this is a 16% solution