In the figure shown, the maximum and minimum currents through Zener diode are 

 

 

 

As 10 kilo ohm is in parallel with Zener then voltage and current across it is constant and the current through the load is $\frac{40}{10\times {10}^3}=4 \mathrm{mA}$

Minimum potential drop across 5 kilo ohm resistor is 70 - 40 = 30 V and current is $\frac{30}{5\times {10}^3}=6 \mathrm{mA}$

current through Zener is 6 - 4 = 2 mA

maximum voltage drop across the 5 Kilo ohm resistor is 110 - 40 = 70 V

maximum current $\frac{70}{5\times {10}^3}=14 \mathrm{mA} \mathrm{maximum} \mathrm{current} \mathrm{through} \mathrm{Zener} 14-4=10 \mathrm{mA}$