Farmer martin is trying to reduce the number of birds in his field. on the first day, he counts 575 birds. on the second day, he adds a scarecrow and reduces the number of birds in his field by one fifth, on the third day he adds a second scarecrow, and counts only 345 birds. if the pattern continues, how many scarecrows will he need to get below 100 birds? ? explain how you got your answer plz