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Homework Statement:
 The rheostat and capacitor bank are connected in parallel and connected to a sinusoidal voltage source of 220 V with a frequency of 50 Hz. The resistance of the rheostat is 20 Ohm, the capacitance of the capacitor bank is 100 μF. Determine the effective current value in the unbranched part of the circuit.
Homework Equations:

1) Xc = 1/(ω*C) = 1/(2*π*f*C)
2) I = U/resistance
Given:
U = 220 V
f = 50 Hz
r = 20 Ohm
C = 100 μF
Find: I
Solution:
1) Xc = 1/(ω*C) = 1/(2*π*f*C) = 1/(2*π*50*10^4) = 31.83 Ohm
2) R_eq  equivalent resistance
R_eq = (r*Xc)/(r+Xc) = (20*31.83)/(20+31.83) = 12.28 Ohm
3) I = U/R_eq = 220/12.28 = 17.9 A
True answer given in the textbook is 13 A.
Could you please tell, what is wrong in the solution?
U = 220 V
f = 50 Hz
r = 20 Ohm
C = 100 μF
Find: I
Solution:
1) Xc = 1/(ω*C) = 1/(2*π*f*C) = 1/(2*π*50*10^4) = 31.83 Ohm
2) R_eq  equivalent resistance
R_eq = (r*Xc)/(r+Xc) = (20*31.83)/(20+31.83) = 12.28 Ohm
3) I = U/R_eq = 220/12.28 = 17.9 A
True answer given in the textbook is 13 A.
Could you please tell, what is wrong in the solution?
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