A machine in a soft drink bottling factory caps 3 bottles per second. How many bottles can it cap in 15 hours?

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