What is the total effective resistance of the two resistors? A 12.4-ohm resistor, R1, and a 30.-ohm resistor, R2, are to be connected in parallel...

For resistors in parallel, the effective resistance will
always be less than the lowest individual resistor in the
circuit.

To find the effective resistance (Re) use the
following formula:

1/Re = 1/R1 + 1/R2 +
...

In your
example:

1/Re = 1/12.4 +
1/30

solving for Re = 8.77
ohms.

Just remember to take the inverse of your answer on
the left to get the value of Re!