He then went to see the oranges being harvested. He found out that they harvested 42 sacks of oranges. How many days did it take to harvest them if they harvested 21 sacks of oranges per day?
1. He went to see the oranges being harvested. 
2. He found out that they harvested 42 sacks of oranges. 
3. How many days did it take to harvest them if they harvested 21 sacks of oranges per day?

We can solve this problem by using division. We know that there were 42 sacks of oranges in total, and that they were harvested at a rate of 21 sacks per day. So, we can divide 42 by 21 to find out how many days it took to harvest the oranges. 

42 ÷ 21 = 2 

It took two days to harvest the oranges.