Question

The port charges an amount from the ship depending on how much time they spent on the port. The graph given below shows the relation between the time spent by ship (in minutes), x, and the amount charged by port (in $\$),y.$
[Hint: Subtitute the coordinates in the given expressions to find the correct equation.]
Interpret the graph and choose the correct conclusions from the graph.

Answer 1

$\begin{array}{cccc}\text{Time spent (in minutes), x}& 10& 20& 30\\ \text{Amount charged by the port (in}\$),y& 200& 400& 600\\ & (200=20\times 10)& (400=20\times 20)& (600=20\times 30)\end{array}$
The graph shows the relation between the amount charged by the port (in $\$),y,$ and the time spent by the ship on the port (in minutes), x. Each value in the amount charged by the port (in $\$),y,$ is obtained by multiplying 20 to the corresponding time spent (in minutes), x.
Hence, the equation for the relation shown in the graph is $y=20\times x\text{or}y=20x$.
Option A is correct.
The amount charged by the port when the time spent is 40 minutes is obtained by putting x = 40 in the equation y = 20x.
Amount charged by the port $=40\times 20=\$800$.
Option B is correct.
The time spent by the ship when the amount charged by the port is $\$100$ is obtained by putting y = 100 in the equation y = 20x
$20\times$ Time spent by the ship = 100
Dividing both sides by 20, we get,
Time spent by the ship $=100÷20=5$ minutes
Option C is correct.
As all the options are correct, option D is the correct choice.