In a parallel circuit, voltage is thee same across each component in the circuit. The sum of the currents through each path is equal to the current from the source. However, the resistance cannot be added directly. It is calculated as:
1/Rt = 1/R1 + 1/R2 + 1/R3 1/Rt = 1/6.8 + 1/9.0 + 1/15
Rt = 3.08 ohms