Fundamentals: Resistors in series and parallel

A 6 V battery with negligible internal resistance is connected to two resistors of 2kohm each. A voltmeter of 2 kohm is used to measure the pd across each resistor. When connected to the 2kohm resistor the reading is 2 V , you would expect the other 2 kohm to have a pd of 4 V. When the voltmeter is used to measure the other 2 kohm the reading is again 2V .Work this out. The true pd is 3 V and can only be obtained if the voltmeter has infinite resistance(ideal voltmeter).