What is the resistance of a circuit section consisting of two parallel-connected 40 and 60 Ohm resistors?

What is the resistance of a circuit section consisting of two parallel-connected 40 and 60 Ohm resistors? What is the resistance of a circuit section consisting of three series-connected 10, 20 and 30 Ohm resistors?

First task:

R1 = 40 Ohm – the value of the first resistance;

R2 = 60 Ohm – the value of the second resistance.

It is required to determine Rtot (Ohm).

According to the problem, both resistors are connected in parallel. Then, the total resistance of the circuit will be equal to:

Rtot = R1 * R2 / (R1 + R2) = 40 * 60 / (40 + 60) = 2400/100 = 24 Ohm.

Answer: Rtotal is 24 Ohm.

Second task:

R1 = 10 Ohm – the value of the first resistance;

R2 = 20 Ohm – the value of the second resistance;

R3 = 30 Ohm – the value of the second resistance.

It is required to determine Rtot (Ohm).

According to the condition of the problem, both resistors are connected in series. Then, on the section of the circuit, the resistance will be equal to:

Rtot = R1 + R2 + R3 = 10 + 20 + 30 = 30 + 30 = 60 Ohm

Answer: Rtotal is 60 Ohm.