Aaron likes to help his mother with chores around the house. He sweeps the floor every $3$ days, mopes the floor every $5$ days, cooks dinner every $9$ days and cleans the windows every $3$ weeks. He does all $4$ chores on the same day today. How many days later will he do all $4$ chores together again? 
Overseas Competition->Knowledge Point->Calculation Modules->Whole Numbers->Extracting Common Factors from Whole Numbers