Resistors in Series & Parallel

R_t = R_1 + R_2 = 9\,\Omega

Total resistance9.00 Ω

Current from supply1.00 A

Power dissipated9.0 W

Resistor R₁6 Ω

Resistor R₂3 Ω

Supply voltage9 V

Wire the resistors in SERIES to get a total above 25 Ω (bigger than either resistor)
Now wire them in PARALLEL and drop the total below 1.5 Ω (below the smaller resistor)
Draw at least 20 A from the supply (think: lowest total resistance, highest voltage)
Dissipate at least 150 W of power (P = V²/R)
Find the smallest total resistance possible (below 0.6 Ω)