KillerSquirrel wrote:
the new ratio is 20:45 = 4:9 ---> meaning that if we had 13ml of 85% solution we now have only 4ml so the part that was replaced is 9/13.
Thanks for the solution but can somebody explain the logic step by step and slowly?
the new ratio is 20:45 = 4:9 ---> meaning that if we had 13ml
[ 4x + 9x = 13 and for the sake of the solution x = 1 hence 13 ml ] of 85% solution[13ml of 85% solution .... what someone should understand by this. If someone tries to find the 0.85 of 13 it will not get int value] we now have only 4ml
[how this magic 4 came up] so the part that was replaced is 9/13.
[by now totally lost]