Q1: An RC high-pass filter consists of an 820  resistor. What is the value of C so that X_c is ten times less than R at an input frequency of 12 kHz?

ANS:C - 0.161 F

Thanks for your effort @Maha but I disagree with the value of your reactive capacitance you wouldn't get the answer if your Xc is 8200 ohm. Xc must be 82 ohms only remember Xc is 10 times less than are meaning your Xc must be smaller than your resistor in that case you can get the value of 0.161 uF.