The Brown family needs to rent a truck for their upcoming move. Express Movers will charge them $25 for the first day and $0.80
for every mile. Smith & Smith Co. will charge $35 for the first day and $0.60 for every mile. Before deciding which service to use, Mrs. Brown wants to find out how many miles would make the two choices equivalent in cost. The following equations represent this situation.
Here, x represents number of miles and y represents the cost.
This situation is shown in the graph.
Here, x represents number of miles and y represents the cost.
This situation is shown in the graph.
2 answers:
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Answer:
The correct option is;
21 ft
Step-by-step explanation:
The equation of the parabolic arc is as follows;
y = a(x - h)² + k
Where the height is 25 ft and the span is 40 ft, the coordinates of the vertex (h, k) is then (20, 25)
We therefore have;
y = a(x - 20)² + 25
Whereby the parabola starts from the origin (0, 0), we have;
0 = a(0 - 20)² + 25
0 = 20²a + 25 → 0 = 400·a + 25
∴a = -25/400 = -1/16
The equation of the parabola is therefore;
To find the height 8 ft from the center, where the center is at x = 20 we have 8 ft from center = x = 20 - 8 = 12 or x = 20 + 8 = 28
Therefore, plugging the value of x = 12 or 28 in the equation for the parabola gives;
.