The ratio of efficiencies of A and B is 2 : 3. Working together, they can complete the work in 16 days, then how much time does A alone take to complete the same work.

40 days

Let the total work be 16 x 5 = 80 (i.e. no. of days x efficiency)

Then, using the same formula time taken by A alone = \(\frac{Total\; work}{Efficiency}\)

                                                                            = \(\frac{80}{2}\) = 40 days