How will equivalent EMF and resistance of cells be calculated
What you have here is just a series connection of batteries, with one in the middle being connected with reverse polarity. To find the equivalent voltage you’d add the voltages according to Kirchhoff voltage law. The result is (from left to right) =1.5V -1.5V + 1.5V =1.5V . Also since they are in series there internal resistances would add and give a total resistance of 6 ohms.