Two resistors are connected (a) in series (b) in parallel. The equivalent resistance in the two cases are 9 ohm and respectively. Then the resistances of the component resistors are

Options

A. 2 ohm and 7 ohm
B. 3 ohm and 6 ohm
C. 3 ohm and 9 ohm
D. 5 ohm and 4 ohm

Answer

B

Explanation

`R_(1)+R_(2)=9" and "(R_(1)R_(2))/(R_(1)+R_(2))=2rArrR_(1)R_(2)=18`
`R_(1)-R_(2)=sqrt((R_(1)+R_(2))^(2)-4R_(1)R_(2))=sqrt(81-72)=3`
`R_(1)=6Omega,R_(2)=3Omega`