Answer:
The answer is below
Step-by-step explanation:
A function show the relationship between an independent variable and a dependent variable. The independent variable (input) does not depend on other variables while the dependent variable (output) depend on other variables.
In this question, amount of water in tank is dependent variable and the time taken is the independent variable. Let y represent amount of water in tank and x represent the time it has been draining. Therefore:
a) This can be represented by the equation:
y = 450 - 20x
At 7 minutes (x = 7)
y = 450 - 20(7)
y = 310 gallons
b) For 200 gallons (y = 200), the time taken is:
200 = 450 - 20x
200 - 450 = -20x
-20x = -250
x = -250/-20
x = 12.5 minutes
c) y = 450 - 20x
d) The graph was plotted using geogebra onling graphing calculator.
e) When the tank is empty, y = 0, hence
0 = 450 - 20x
20x = 450
x = 450 / 20
x = 22.5 minutes
