Work done by A in one hour: 2x

Work done by B in one hour: x

Number of days taken by A and B to do the work together: 12 hours

Work done by A and B together in one hour: \(\frac{1}{12}\)

\(\frac{1}{12}\) = 2x + x

\(\frac{1}{12}\) = 3x

X = \(\frac{1}{36}\)

Here X is Work done by B in one hour

∴ B alone will take 36 hours to complete the work.