Transistor Circuit question
The answer given is clearly wrong.

20 volts across a 10K resistor will give 2 mA, so \$I_0\$ can't possibly be 600 mA.

If we omit the transistor, the two 10K resistors form a voltage divider, dividing the 20 volt supply in half, making \$V_0\$ 10 volts.

The transistor will draw some current in parallel with the lower 10K, so \$V_0\$ must be less than 10 volts.