What is the current flowing in a circuit which has two resistors of 4 ohms each connected in parallel to a power source of 24 volts?

Three 214 K Ohm resistors in series is 656 K Ohms. Across 24 volts, that is about 0.03659 milliamperes.

Three 214 K Ohm resistors in parallel is about 71.3 K Ohms. Across 24 volts, that is about 0.3364 milliamperes.

RSeries = SummationI=1toN (RI)

RParallel = 1 / SummationI=1toN (1 / RI)

Current = Voltage / Resistance