check the picture below.
notice, a function that is decreasing, namely have a negative slope, doesn't have to be negative.
You can set up a system of equations for this problem. x= number of coach tickets and y = number of first class tickets.
$210x + $1200y = $10,230 (cost of coach ticket plus cost of first class tickets is total budget)
x + y = 11 (number of coach tickets plus number of first class tickets is total number of people)
Solve the second equation for y to get y = 11 - x, then plug that into the first equation and solve for x:
$210x + $1200(11 - x) = $10,230
$210x + $13,200 - $1200x = $10,230
-$990x + $13,200 = $10,230
-$990x = $2,970
x = 3
Sarah bought x = 3 coach tickets. Plug that into the second equation and solve for y:
3 + y = 11
y = 8
Sarah bought y = 8 first class tickets.
A + b = d+c
<span>a - b = e - c </span>
The b and c cancel out.
<span>2a = d+e </span>
<span>a = (d+e)/2 </span>
We have been given that Tim spends about 1/3 of each weekday sleeping and about 7/24 of each weekday in school. And we need to find what fraction of the weekday does Tim spend either sleeping or in school.
This means that we need to find the time he spends in sleeping when he is in the school.
Therefore, we have to add the time he spends in sleeping and the time he spends in school.
Therefore, required fraction is given by

Now in order to add the fractions, we have to make the denominator same.
Multiply the numerator and denominator of first fraction by 8 to make the same denominator.

Now, we have the same denominator hence, we can add the numerator


Therefore, Tim spends 15/24 hours each weekday sleeping in the school.
I don't understand your question.. Is this multiple choice or something else?