For doing a certain work, the efficiencies of A, B and C are in the ratio 2 : 3 : 5. Working together, they can complete the same work in 15 days. B and C can complete 80% of the original work in:
If \({sin\theta\over1+cos\theta}+\)\({1+cos\theta\over sin\theta}\)\(={4\over \sqrt3}\), \(0^0<\theta<90^0\), then the value of \((tan\theta+sec\theta)^{-1}\) is :