Question

In the circuit given below, the value of R is ____________

(a) 12 Ω

(b) 6 Ω

(c) 3 Ω

(d) 1.5 Ω

Answer 1

Right choice is (b) 6 Ω

For explanation I would say: The resistance of parallel combination is given by,

Req = \(\frac{40}{3}\) – 10 = 3.33 Ω

Or, \(\frac{1}{3.33} = \frac{1}{12} + \frac{1}{15} + \frac{1}{15}\)

Or, R = 6 Ω.