Answer:
68 ohm
Explanation:
Output Voltage, Vout = 5 V
Forward voltage, Vf = 3.65 V
Forward current, If = 20 mA = 0.02 A
Let the resistance is R.
Use the formula
[tex]I_{f}=\frac{V_{out}-V_{f}}{R}[/tex]
[tex]0.02=\frac{5-3.65}{R}[/tex]
R = 67.5 ohm
R = 68 ohm ( approx.)