Answer:
42.8572 L of 30% HCl and 7.1428 L of 45% HCl would be needed to mix and produce 50 liters of 35% HCl.
Step-by-step explanation:
Let volume of 30% HCl solution required to make 35% of HCl solution be x
Volume of 45% of HCl required to make 35% of HCl solution be y
Volume of solution required = 50 L
x + y = 50 ..(1)
30% of x +45 % of y = 35% of 50

3x + 45y = 1750 ..(2)
Solving equation (1) and (2):
x = 42.8572 L
y =7.1428 L
42.8572 L of 30% HCl and 7.1428 L of 45% HCl would be needed to mix and produce 50 liters of 35% HCl.