I was trying to resolve the following problem  : "A 6.8 kΩ resistor, a 7 mH coil, and a 0.02 uF capacitor are in parallel across a 17 kHz ac source. The coil's internal resistance, RW, is 30 Ω.

The equivalent parallel resistance, Rp(eq) is"

But the correct of the exercise says it's 18 Ω and this answer doesn't make no sense to me.

Actually, to find the answer, I calculated the sum of admittances Y then I expressed R (the real part of the impedance Z) as R = G/G^2+B^2 with G being the conductance et B the susceptance. I started by calculating XL and XC then I calculated G and B and finally applied this formula R = G/G^2+B^2 that I got starting from the fact that we know that Z = 1/Y

By doing that, I found that the equivalent resistance is equal to 294.2 Ω which is far from 18 Ω.

Would you have any clues of why the correction says that the answer is 18 Ω? This really makes no sense to me..

Thank you

I was trying to resolve the following problem:

A 6.8 kΩ resistor, a 7 mH coil, and a 0.02 uF capacitor are in parallel across a 17 kHz ac source. The coil's internal resistance, RW, is 30 Ω.

The equivalent parallel resistance, Rp(eq) is

But, the correct of the exercise says it's 18 Ω, and this answer doesn't make sense to me.

Actually, to find the answer, I calculated the sum of admittances Y then I expressed R (the real part of the impedance Z) as R = G/G^2+B^2 with G being the conductance et B the susceptance. I started by calculating XL and XC then I calculated G and B and finally applied this formula R = G/G^2+B^2 that I got starting from the fact that we know that Z = 1/Y

By doing that, I found that the equivalent resistance is equal to 294.2 Ω which is far from 18 Ω.

Would you have any clues of why the correction says that the answer is 18 Ω? This really makes no sense to me.