Answer:
1.25 liters of oil
Step-by-step explanation:
Volume in Beaker A = 1 L
Volume of Oil in Beaker A = 1*0.3 = 0.3 L
Volume of Vinegar in Beaker A = 1*0.7 = 0.7 L
Volume in Beaker B = 2 L
Volume of Oil in Beaker B = 2*0.4 = 0.8 L
Volume of Vinegar in Beaker B = 1*0.6 = 1.2 L
If half of the contents of B are poured into A and assuming a homogeneous mixture, the new volumes of oil (Voa) and vinegar (Vva) in beaker A are:

The amount of oil needed to be added to beaker A in order to produce a mixture which is 60 percent oil (Vomix) is given by:

1.25 liters of oil are needed.