1. The problem statement, all variables and given/known data
i am wondering if this is correct. this is the question;
Three cells, each of e.m.f. 1·5 V and internal resistance 0·50 Ω, are connected in series to
make a battery of e.m.f. 4·5V. The battery is connected to a resistor, R, of resistance 6·0 Ω.
2. Relevant equations
3. The attempt at a solution
TOTAL VOLTAGE = 4.5V
TOTAL RESISTANCE = 6.5 OHMS
but the answer states the total resistnace is 7.5 ohms.
can someone kindly explain how?