Answer: 30 minutes.
Step-by-step explanation:
Given : Brett, Lucy, and Donnie are each making trips carrying bags of mulch from the back losing dock to the front of the store.
It takes Brett 3 minutes to make a trip , Lucy 5 minutes to make a trip and Donnie 6 minutes to make a trip.
Then , the number of minutes at which they all arrive back at the same time= Least common multiple of 3,5, and 6 i.e. LCM(3, 5, 6)
Prime factorization :-
[tex]3=3\times1\\5=5\times1\\6=3\times2\times1[/tex]
Then, [tex]\text{LCM(3, 5, 6)}=3\times2\times5=30[/tex]
Hence, they all arrive after 30 minutes at the time.
