To do a certain work, the ratio of efficiency of A to that of B is 5 : 9. Working together, they can complete the work in 10\(\frac{1}{2}\) days. They work on it together for 8 days. Now find in how many days A alone will do 80% of the remaining work?

5\(\frac{3}{5}\)

Efficiency : A  :   B = 5 : 9 = 14

Total work = 14 × \(\frac{21}{2}\) = 147

Work done in 8 days = 14 × 8 = 112

Remaining work = 147 - 112 = 35

80% of remaining work = 35 × \(\frac{80}{100}\) = 28

Time taken by A = \(\frac{28}{5}\) days