Question

Please tell me answer fast tomorrow is my exam

Answer 1

if circuit is closed
effective resistance=
$\frac{10 \times 5}{10 + 5} + \frac{5 \times 10}{10 + 5} \\ = \frac{50 + 50}{15} \\ = \frac{100}{15} = \frac{20}{3}$
if circuit is open effective resistance
$= \frac{15}{1 + 1} = \frac{15}{2}$