Answer :
Let the amount of proper amount of water to be added be x milliliters.
the solution of 100 milliliters is 2% saline, means that 2%*100=2 milliliters of the original solution is saline.
after we add x milliliters, the total volume of the liquid becomes 100+x (milliliters), and 2 milliliters is now 0.9% of the solution, that is:
2 = 0.9% (100+x)
2=0.9+0.009x
0.009x=2-0.9
0.009x=1.1
x=1.1/0.009=122.2 (milliliters)
Answer: 122.2 milliliters
the solution of 100 milliliters is 2% saline, means that 2%*100=2 milliliters of the original solution is saline.
after we add x milliliters, the total volume of the liquid becomes 100+x (milliliters), and 2 milliliters is now 0.9% of the solution, that is:
2 = 0.9% (100+x)
2=0.9+0.009x
0.009x=2-0.9
0.009x=1.1
x=1.1/0.009=122.2 (milliliters)
Answer: 122.2 milliliters