Whenever, workers are working alternatively on one work, we take 2 as 1 unit
In this case, we take 2 hours as 1 unit.
Part of the field moved by Ganga and Saraswati in 2 hours (1 unit) =
Time taken to complete the work,
unit of time
Then actual time taken by them to complete the work,
= 9.6 hours
The work starts at 9 a.m. then it will complete at 6:36 pm
% of the field moved by Ganga and Saraswati in 2 hours (1 unit),
= 12.5 + 8.33
Time taken to move the whole field,
= 4.8 unit of time;
Hence, actual time = 2 × 4.8 = 9.6 hours.