Step 1: Fill a ten-catty oil drum with three-catty small gourds, then pour the oil from the three-catty small gourds into a seven-catty big gourds, and circulate for three times.

At this time, the oil drum is filled with oil1kg; There are 7 pounds of oil in the gourd; There are 2 Jin of oil in the gourd.

Step 2, pour the oil in the gourd into the oil drum; Pour the oil from the small gourd into the big gourd.

At this time, there are 8 kilograms of oil in the oil drum; There are 2 Jin of oil in the gourd; There is no oil in the gourd, it is zero.

Step 3, fill the oil barrel with a small gourd, and then pour the oil in the small gourd into the big gourd;

At this point, there are 5 kilograms of oil in the oil drum; There are 5 Jin of oil in the gourd; There is no oil in the gourd, it is zero.

Five Jin each, share it.