Carcass wrote:
There are 8 fields of exactly the same size that are to be plowed by 7 farmers who work at identical rates. If it takes 5 hours for 4 of the farmers to plow the first 2 fields, how many hours will it take the remaining 3 farmers to plow the remaining 6 fields?
Amount of work = Rate * time
Now for the first case
"5 hours for 4 of the farmers to plow the first 2 fields"
it can be written as:
\(2 = 4 * Rate * 5\)
or Rate = \(\frac{2}{20} = \frac{1}{10}\)
Now, time taken for 3 farmers to plow the remaining 6 fields
Amount of work = Rate * time
\(6 = 3 * \frac{1}{10} * Time\)
or Time = 20 hours