Question

Sita can finish work in 12 days working 4 hours a day. Gita can finish the same work in 15 days working 3 hours a day. In how many days can they finish it working together at 4 1/2 hours a day?

Answer 1

Sita can complete the work in 12 * 4 = 48 days.

Sita's 1-day work = 1/48.

Gita can complete the work in 15 * 3 = 45 days.

Gita's 1 - day work = 1/45.

(Sita + Gita)'s 1'day work = 1/48 + 1/45

                                         = 1 * 15 + 1 * 16/720

                                         = 15 + 16/720

                                         = 31/720.


So, Sita and Gita can finish the work in 720/31 hours.

Therefore the number of days of 9/2 hours each = (720/31) * (2/9)

                                                                                   = 2 * 720/31 * 9

                                                                                   = 1440/279

                                                                                   = 160/31.

                                                                                   = 5 5/31 days.


Hope this helps!

Answer 2

This is ur ans hope it will help you in case of any doubt comment below