For this case we have by definition, if "y" varies directly with "x", then it is true that:

Where:
k: It is the constant of proportionality
We have the following equation:

So, as mentioned above we have to:

Answer:

Option B
I think 45 but not too sure, lol sry
Answer:
c = 15d + 30
Step-by-step explanation:
Hey there!
This can be represented by an equation of a line, where the number of days is our x-values(d), and the price is our y-values(c).
The price for one day ($45) and the price for 4 days($90) are specific points on that line.
The points are (1, 45) and (4, 90).
We can first find the slope of the line:
- As the price rises 45, the days increase by 3
- Slope = rise/run
- Slope = 45/3
- Slope = 15
Now we can find the base price, by plugging the slope and a point into the equation y = mx + b.
Solve for b:
- y = mx + b
- 45 = 15(1) + b
- 45 = 15 + b
- 30 = b
The base price (b) is 30.
The equation is 
Let the two numbers be x and y, then
x + y = 62 . . . . . . . (1)
x - y = 18 . . . . . . . .(2)
subtracting (2) from (1), we have:
2y = 44
y = 22
From (2), x + 22 = 62
x = 62 - 22 = 40
therefore, the two numbers are 40 and 22.