I am a beginner in electronics and i try to understand the circuit below. But i don't understand why the voltage between the resistors is 13.56 volts?

because the difference in voltage between the diode en the powersupply is: 24-3=21 so the voltage in between the resistances must be 10.5 right?

So i don't understand why it is 13.56? Hopefully someone can help me with this! thanks in advance!