Try to use these formula to solve the problem . Answer is 3

But sir the circuit which you have drawn the polarity of e2 and E3 is same so why it's not substracted

See in series circuit, oppoiste terminals should be connected(positive terminal to negative terminal and viceversa) ,otherwise -E will come

In parallel circuit, same terminals have to be connected(positve terminals of all battery connected together and negative terminals of all batteries connected together), otherwise -E will come

After simply the series circuit got the simple parallel combination but the answer come by the substraction of emf even they are of same polarity in parallel

My doubts has got cleared

Than you so much sirk