22 ducks were spotted and tagged one day in Swan Lake. One week later 21 ducks were spotted. Of those 21 ?

Question

ducks 7 had been tagged the week before. Predict how many ducks are in Swan Lake.

Please explain how you arrived at the answer.

Answer 1

well u said that a week b4 7 duccs have already been tagged.

so wut u would do is subtract 7 from 21: 21-7=14.

now wut u would do is add 14 to 22: 22+14=36.

so there is a total of 36 duccs in Swan Lake.

Answer 2

I'm just looking at this as a counting problem, so i could be completely wrong.

22 + 21 = 43

However, of these 43, 7 were counted twice

So, you have

43-7=36 ducks

Answer 3

This is a guess : 66

22 ducks were tagged one week.

The next week, 7 out of 21 (1/3) ducks spotted were tagged.

Based upon the second sample, I am assuming that there are two untagged ducks for each tagged duck. So, 22 + 2(22) = 66.