In an electric circuit, two resistors with resistances 3ohm and 5 ohm are connected in parallel. In this case, if R is the combined resistance of these two resistors, then the reciprocal of R is equal to the sum of the reciprocals of two resistors. What is the value? Options.
A) 15 ohms
B) 15/8 ohms
C) 1/8 ohms
D) 8/15 ohms
E) 8 ohms
The wording is a bit confusing, though basically we are told that 1/R = 1/3 + 1/5, from which it follows that R=15/8ohms.   Answer: 15/8 ohms.
<result>B</result>
In an electric circuit, two resistors with resistances 3ohm and 5 ohm are connected in parallel. In this case, if R is the combined resistance of these two resistors, then the reciprocal of R is equal to the sum of the reciprocals of two resistors. What is the value?