Two wires of same metal have the same length but their cross-sections are in the ratio $3:1$. They are joined in series. The resistance of the thicker wire is $10\,\Omega $. The total resistance of the combination will be ............. $\Omega$
  • A$40$
  • B$\frac{{40}}{3}$
  • C$\frac{5}{2}$
  • D$100$
AIPMT 1995,AIIMS 2012, Medium
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