Answer:
5 minutes
Step-by-step explanation:
let the time after which two lines will have filled an equal number of barrels is 'X' minutes.
so, according to the question after 'X' minutes;
⇒ number of barrels in old conveyer line = number of barrels in new conveyer line
⇒ [tex]40+2X=10X[/tex]
⇒ [tex]X=5[/tex]