Assume the resistance values are $R_{1}=2400 \Omega, R_{2}=1400 \Omega, R_{3}=4500 \Omega,$ and $R_{4}=6000 \Omega,$ and the battery emfs are $\varepsilon_{1}=1.5 \mathrm{V}$ and $\varepsilon_{2}=3.0 \mathrm{V},$ unless stated otherwise.
Analyze the circuit in Figure P19.48.
a. Express the resistors in parallel as a single equivalent resistor. What is the value of this resistor?
b. Combine this equivalent resistor with $R_{1}$ to get the total equivalent resistance of the circuit. What is the value of this resistor?
c. The circuit is now "reduced" to a battery in series with a single equivalent resistance. Use your result from part (b) to find the current through the battery and resistor $R_{1}$.