Flea collars thrown away per year = 50 million
Flea collars thrown away per day = 50 million/Average number of days in a year
Average number of days in a year = 365 days
Therefore,
Flea thrown away per day = 50,000,000/365 = 136,986.3
Rounding the answer to nearest thousand,
Number of flea thrown away per day = 137,000