You have a circuit consisting of one resistor and one ideal battery. In that circuit the current supplied by the battery is 2.60 A. A second resistor is added to the circuit, and the current supplied by the battery changes to 3.50 A. Because the current has increased, we know the second resistor should have been added in parallel with the first.
1. Compute the ratio of the resistance of the first resistor to the resistance of the second resistor.
2. The circuit is now re-wired; therefore that it is a series circuit with the battery and the resistors all in series with one another. What is the current now?