(a) The total resistance of two 100 ohm resistors connected in series is:
R_total = R_1 + R_2 = 100 ohms + 100 ohms = 200 ohms
(b) The total current flowing in the circuit can be calculated using Ohm's law:
V = I * R
where V is the voltage of the battery, I is the current flowing in the circuit, and R is the total resistance of the circuit.
Rearranging the equation, we get:
I = V / R
Substituting the given values, we get:
I = 1.5V / 200 ohms
I = 0.0075 A or 7.5 mA
Therefore, the total current flowing in the circuit is 7.5 mA.