Answer:
2.22 hours
Explanation:
If Sally can paint the office by herself in 5 hours, we can say that in one hour she paints 1/5 of the office.
On the other hand, Lucy paints the office in 4 hours, which means that, in 1 hour she paints 1/4 of the office.
Therefore, to know how much they would paint per hour working together, we are going to sum up the fractions they paint per hour:

Therefore, working together they will paint
of the office in one hour.
Now we can establish a rule of three: if they paint 0.45 of the office in 1 hour, how long (x) will it take them to paint 1.0 of the office?

And therefore 
Therefore, it will take them 2.22 hours to paint the office working together.
I believe the answer is: proximodal trend
Proximodal trend refers to the period when children started to develop more specific muscle/ motor skills.
For people in general, our upper body tend to be developed at much faster rates compared to our lower body, which cause infants having to crawl first before they are able to walk.
Me: Hello
He: Hi
Me: How are you?
He: good and you
Me: How old are you?
He: I have 15 years old
Me: I also have the same
He: what’s your name
Answer:
it represents in the first one