A is 20% more efficient than B. How much time will they working together take to complete a job which A alone could have done in 29 days ?

$\frac{174}{11}$

A is 20% more efficient than B i.e;

\(\frac{A}{B}\) = \(\frac{120}{100}\) = \(\frac{6}{5}\)

⇒ Efficiency (A = 6, B = 5),

 A finishes work in 29 days,

therefore, total work = 6 x 29 = 174      .. (Efficiency × Days = Total work)

⇒ Time taken to complete the work by working together = \(\frac{174}{6+5}\)

 = \(\frac{174}{11}\) days.