What will the electricity bill be, assuming the energy costs 15 fills per unit?

when a device is used in a circuit in which the voltage is 81 v, the current flowing through the device is 3 a. what is the resistance of the device?

a. 27 ω

b. 40.5 a

c. 243 ω

d. 243 a

the correct answer is a. 27

the answer is f1 and d2 because if you put equal force on those two points the beam would balance trust me on this