How could we find the current that passes through each resistor in this circuit? The problem is that we don't have the voltage of each resistor to find the current, because the voltages of the resistors are not equal to the voltage of the source.
Start by labelling your circuit. You should know that in a series circuit, the current is the same at any point in the circuit.
We know that because this is now a series circuit, the current at each arrow in the circuit is the same. To find the current in the circuit, just work out the parallel resistance of each branch and use Ohms Law.
Once you have done this, you can find out the voltage drop over each parallel branch, once again employing Ohms Law.
Once you have done this, you can simply apply Ohms Law to each resistor to find the current through it. To make sure you have done it right, just remember the total current in each parallel branch should equal the total current of the circuit.