you will get brainliest if u show work

Answer:
i hope my answer help u
Step-by-step explanation:
it will be 10 classrooms
cuz 75min. = 5 ×15min.
and he said that the custodian can clean 2 classrooms in 15 min.
so we will do 2 × 5 = 10 classroons in 75 minutes