1. The problem statement, all variables and given/known data Schematic of circuit is not given, only the text which I translated into English. Using a voltmeter with internal resistance of 6k ohm, voltage between two points, 1 and 2 of a circuit of constant current, is measured to be 8v. Then, using a voltmeter with internal resistance of 10k ohm, between the same points, voltage is measured to be 12v. What voltage will the voltmeter with internal resistance of 15k ohm measure? 2. Relevant equations I=U/R 3. The attempt at a solution I tried to solve it by calculating currents getting 1.3mA and 1.2mA in first and second case, but wasn't sure what to do next. These voltmeters should be represented as resistors and the answer is 16V.