Answer:
54minutes
Step-by-step explanation:
Let the time taken to clean up be t
Let the number of people cleaning be n
If the time it takes to clean up after an anniversary party varies inversely as the number of people cleaning then;
t = k/n
k is the constant of proportionality
If 3 people work together to clean, and took them 90 minutes, this means
at t = 90, n=3
Substitute
90 = k/3
k = 3×90
k = 270
To et the time it will take 5people to clean, the will say;
t =k/n
t =270/5
t = 54 minutes
Hence it will take 5 people 54minues to clean