You are hired to count the number of ducks on three northern lakes during the summer. in the first lake, you estimate 500,000 ducks, in the second 250,000 ducks, and in the third 100,000 ducks. you write down that you have counted 850,000 ducks. as you drive away, you see 15 ducks fly in from the south and land on the third lake. do you change the number of ducks that you report? justify your answer.