Answer:
150 mL
Step-by-step explanation:
We need a mixture that is at 50%, now we have 200 mL at 35% and another mixture that is at 70%, that is, we must calculate how much of this mixture is added, by the following equation
200 * 35% + x * 70% = 50% (x + 200)
70 + 0.7 * x = 0.5 * x + 100
0.7 * x - 0.5 * x = 100 - 70
0.2 * x = 30
x = 30 / 0.2
x = 150
150 mL must be added so that the mixture is 50%.
Its equally distant from the endpoints of the segment to find the center of the following rotation
