What is the equivalent resistance of a circuit with parallel resistances of 5 ohms and 15 ohms?

To find the equivalent resistance of resistors in parallel, you can use the formula:

1/R_total = 1/R1 + 1/R2

Here, R1 is 5 ohms and R2 is 15 ohms. Plugging those values into the formula gives:

1/R_total = 1/5 + 1/15.

To combine these fractions, you need a common denominator. The least common multiple of 5 and 15 is 15. Therefore:

1/5 = 3/15 and 1/15 = 1/15.

Now you can add these together:

1/R_total = 3/15 + 1/15 = 4/15.

To find R_total, take the reciprocal:

R_total = 15/4 = 3.75 ohms.

This calculation shows that the equivalent resistance for the 5 ohm and 15 ohm resistors in parallel is accurately determined to be 3.75 ohms. The understanding of how to apply the parallel resistance formula effectively leads to the right answer in this scenario.