Question

What is the voltage drop across R4 in the diagram shown above?

Answer 1

R₂ and R₃ can be replaced by:

$R_5 = \frac{1}{\frac{1}{R_2} + \frac{1}{R_3}} = 106 \frac23$

The total R of the circuit is R₁+R₅+R₄ = 706 2/3

So the current in the circuit I=V/R is 100/(706 2/3) = 15/106 A
(I'm deliberately not trying to round the result)

The voltage drop over R₄ is V=I*R = 15/106 * 500 ≈ 70

So answer C would be my choice.