Check the picture below.
you can pretty much count those lengths off the grid.
recall that A = 1/2 bh.
Answer:
The amount of water must be added to this task = 60 ![cm^{3}](https://tex.z-dn.net/?f=cm%5E%7B3%7D)
Step-by-step explanation:
Let amount of water added = x ![cm^{3}](https://tex.z-dn.net/?f=cm%5E%7B3%7D)
Then from the given conditions
A chemist would like to dilute a 90-cc solution that is 5% acid to one that is 3% acid. So
90 (0.05) = 0.03 ( 90 + x )
4.5 = 2.7 + 0.03 x
0.03 x = 1.8
x = 60 ![cm^{3}](https://tex.z-dn.net/?f=cm%5E%7B3%7D)
Therefore the amount of water must be added to this task = 60 ![cm^{3}](https://tex.z-dn.net/?f=cm%5E%7B3%7D)