Question: While at the lake, Cohen saw 300 fish-eater birds that had migrated into the area recently walking by the lake, eating the fish they had caught. The number of birds at the lake doubled on the second day and reduced by 200 on the third day. How many fish-eater birds did Cohen see in the three days?
Solution:
Since there were 300 fish-eater birds in the lake on the first day, the number doubled to 2*300 = 600 birds on the second day.
The total number of fish that Cohen saw in the lake in the two days is 600+300 = 900
On the third day, the number of fish in the lake reduced to 600-200 = 400 birds
In the three days, Cohen saw 400+900 = 1300 fish-eater birds at the lake.
Answer: 1300