In an electric circuit, two resistors with resistances A and B are connected in parallel. In this case, if r is the combined resistance of these two resistors, then the reciprocal of C is equal to the sum of the reciprocals of A and B. What is C in terms of A and B? Answers:
A) (A-B)/AB
B) (A+B)/AB
C) A+B
D) AB
E) AB/(A + B)
The wording is a bit confusing, though basically we are told that 1/C= 1/A + 1/B, from which it follows that C=AB/(A + B).   Answer: AB/(A + B)
<result>E</result>
In an electric circuit, two resistors with resistances A and B are connected in parallel. In this case, if r is the combined resistance of these two resistors, then the reciprocal of C is equal to the sum of the reciprocals of A and B. What is C in terms of A and B?