so 3 bottles per second so in 1 second it produces 3 times 1=3 bottles in 2 seconds it produces 2 times 3=6 bottles in x seconds, it produces 3x bottles so
15 hours
1 hour=60 minutes
1 minute=60 seconds
1 hour=60 (60 seconds)=60 times 60 seconds=3600 seconds
15 hours=15 times 3600=54000 seconds
so insert/subsitute
number of bottles=3x
in 15 hours=3 times 54000=162000
162,000 bottles in 15 hours