A potential difference of 60 V is applied across the resistor `R_1` and the two resistors in series `R_2` and `R_3` .
The current flowing through resistor `R_1` due to the voltage applied is `I_(R_1) = 60/(R_1)` . The current that flows through `R_2` and `R_3` is the same. It leads to a potential difference of 30 V across `R_2` . This gives the current `I_(R_2) = 30/(R_2)`
The total current of 2 A is the sum of `I_(R_1) = 60/(R_1)` and `I_(R_2) = 30/(R_2)` . It is not possible to solve the equation `2 = 60/(R_1) + 30/(R_2)` for a unique value of `R_1` .
The data provided is not sufficient to determine the resistance of `R_1`