Answer:
72 liters of 35% acid solution and 8 liters of 85% acid solution
Step-by-step explanation:
This is a very simple mixture problem.
We let the number of liters of 35% acid solution be "x"
and
let the number of liters of 85% acid solution be "y"
Now,
we can say:
0.35x + 0.85y = 0.4(80) [we have followed "Percentage*amount" ]
Also, we know two solution amount would be 80 liters, thus we can say:
x + y = 80
or x = 80 - y
Now we substitute this into 1st equation and solve for y first. Shown below:
![0.35x + 0.85y = 0.4(80)\\0.35x + 0.85y = 32\\0.35(80-y)+0.85y=32\\28-0.35y+0.85y=32\\0.5y=4\\y=8](https://tex.z-dn.net/?f=0.35x%20%2B%200.85y%20%3D%200.4%2880%29%5C%5C0.35x%20%2B%200.85y%20%3D%2032%5C%5C0.35%2880-y%29%2B0.85y%3D32%5C%5C28-0.35y%2B0.85y%3D32%5C%5C0.5y%3D4%5C%5Cy%3D8)
Thus, x = 80 - 8 = 72
So we use 72 liters of 35% acid solution and 8 liters of 85% acid solution