Consider the circuit shown in the figure below. (Assume R1 = 12.0 Ω and R2 = 6.00 Ω.)

Question

Read this for the figure -

A rectangular circuit begins at its left side at a 25.0 V battery with the positive terminal on top. From the battery, the circuit extends up and to the right to point b. The circuit continues rightward from point b and splits into three parallel vertical branches. The leftmost branch has a resistor labeled R1, the middle branch has a resistor labeled R2 and the rightmost branch, from top to bottom, goes through a resistor labeled R2, point c, then and a resistor labeled 20.0 Ω. The three branches recombine, the circuit extends to the left passing through point a, bends upward to a resistor labeled R1 and reaches the negative terminal of the battery.

(a) Find the potential difference between points a and b. = The answer is 5.61 volts.
(b) Find the current in the 20.0-Ω resistor. = ??????