1) Answer: 21
As y varies directly with x, this means that the ratio y/x is always a constant.
In other words, the equation can be written as y = kx, where k is a constant term.
Thus,
y = 21
2) Answer: C
Exactly the same process as above.
Here's another method:
25 = k(140)
k = 25/140 = 5/28
Thus, when y = 36, 36 = kx
36 = 5/28(x)
36 * 28/5 = x; x = 201.6
3) 9 = k(12)
9/12 = k and k = 3/4
4) On the graph, it hits y = 1 at x = 4.
Thus, we can rewrite the equation as:
y = (1/4)x, where the constant term is 1/4
5) y = kx
The distance represents the x-ordinates, and the time represents the y-ordinates.
9.5/475 = 0.02
4 = 0.02(x), in hours.
x = 200 miles.
As y varies directly with x, this means that the ratio y/x is always a constant.
In other words, the equation can be written as y = kx, where k is a constant term.
Thus,
y = 21
2) Answer: C
Exactly the same process as above.
Here's another method:
25 = k(140)
k = 25/140 = 5/28
Thus, when y = 36, 36 = kx
36 = 5/28(x)
36 * 28/5 = x; x = 201.6
3) 9 = k(12)
9/12 = k and k = 3/4
4) On the graph, it hits y = 1 at x = 4.
Thus, we can rewrite the equation as:
y = (1/4)x, where the constant term is 1/4
5) y = kx
The distance represents the x-ordinates, and the time represents the y-ordinates.
9.5/475 = 0.02
4 = 0.02(x), in hours.
x = 200 miles.