Answer:
7=X+Y there are 4 adults and 3 children
Step-by-step explanation:
It appears the question is asking you to make mathematical statements.
Basically, just find a way to use the numbers above to make your own addition and subtraction problems.
ADDITION
2.47 + 7.1 = 9.57
7.1 + 2.47 = 9.57
SUBTRACTION
9.57 - 7.1 = 2.47
9.57 - 2.47 = 7.1
To rephrase your question,
Does 
hold the form of 
?
The answer is <em>yes</em>.
Hope this helps.
Note:
Pedantic answer should be considered. In the above answer 
is not a function but rather an equation of a line.
One hour and forty-five minutes
From 4:30 to 5:00 it's 30 minutes, from 5:00 to 6:00 it's one hour (we are at 1 hour and 30 minutes now), and from 6:00 to 6:15, it's 15 minutes.
In total, it's 30 minutes+1 hour+15 minutes which can be rearranged to say
1 hour+30 minutes+15 minutes that you can simplify to 1 hour+45 minutes or
1 hour and 45 minutes
