When there are two power supply circuit, the voltage solution problem?
Could it be that R1 and R2 are interchanged or V1 and V2?
From a conceptual analysis, you really have a voltage divider. Because R1 is equal to R2, the voltage difference between V1 and V2 is divided by two. 5V / 2 = 2.5V. Therefore, the voltage 'Va' will be 2.5V + 10V.
Mathematically you can see it in the schematic.







simulate this circuit &ndash; Schematic created using CircuitLab