## College Physics (4th Edition)

$R = 5.0~\Omega$
We can find the equivalent resistance of the circuit: $R_{eq} = \frac{emf}{I}$ $R_{eq} = \frac{93.5~V}{17~A}$ $R_{eq} = 5.5~\Omega$ Note that: $~5.5~\Omega - 4.0~\Omega = 1.5~\Omega$ We can find the value of $R$: $\frac{1}{1.5} = \frac{1}{2.0}+\frac{1}{R+1.0}$ $\frac{1}{1.5} - \frac{1}{2.0}=\frac{1}{R+1.0}$ $\frac{1}{6.0}=\frac{1}{R+1.0}$ $6.0 = R+1.0$ $R = 5.0~\Omega$