If \({sin^2\theta\over tan^2\theta-sin^2\theta}=5\), then the value of \(\frac{24\cos^2\theta-15\sec^2\theta}{6\ \rm cosec^2 \theta-7\cot^2\theta}\) is:
A and B can do a piece of work in 36 days. B and C can do the same work in 60 days. A and C can do the same work in 45 days. In how many days can A alone complete the same work?