Art of Electronics - Study support

[Wimberleytech]

When a V-O-M says 10k Ohms/Volt, it means 'volts full scale'.  If you are on a 1V scale, the input resistance is 10k * 1v or 10k Ohms.  If you are on a 20V scale, the input resistance is 10k * 20 or 200K Ohms.  So, without being told what scale the meter is set to, it isn't really possible to get the right answer.

A better explanation is here:

https://www.allaboutcircuits.com/textbook/direct-current/chpt-8/voltmeter-impact-measured-circuit/

But they screwed up R4 in the schematic.