Question

If R is the total resistance for a parallel circuit with two resistors of resistance r1 and r2, then . Find the resistance, r1, if the total resistance R is 20 ohms, and r2 is 75 ohms. Round your answer to the nearest ohm if necessary. 1/R = 1/r1+1/r2

Answer 1

Adding and Subtracting Rational Expressions Quick Check:

1. A. (x+4)(x-3)(x+5)

2. D. w+4/w-5

3. D. b-10/b-1

4. A. -3/5

5. C. 27 ohms

Explanation:

Answer 2

For a parallel circuit with two resistors, the total resistance is calculated from the expression:

1/R = 1/R1 + 1/R2

We are given the total resistance, R, which is 20 ohms and R2 which is 75 ohms. We calculate R1 as follows:

1/20 = 1/R1 + 1/75
1/R1 = 11/300
R1 = 27.27 ohms