Step-by-step explanation:
The number of people to paint the bridge is inversely proportional to the number of hours it takes.
(If there are more people, it will take less time etc.)
9 people can paint the bridge in 5 hours.
=> 2 people can paint the bridge in 5 * (9/2) = 22.5 hours.
Answer:

Step-by-step explanation:
and
does not have any common factor except for 
Let, the number be "a"
Now, according to the question,





So, the number is 72
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