Alex wants to find out how many ducks there are in a park.
One day he puts a tag on each of 30 of the ducks.
The next day he catches 40 ducks.
8 of these ducks have tags on them.
Work out an estimate for the number of ducks in the park.
There were 30 the first day. The second day, 8 of those 30 were there as well, so we subtract that from the 40 ducks and get 32. Add 30 and 32 to get our estimate.
