Question

At time x=​0, water begins to drip steadily out of a water tank. After 3 hours ​, there are 6.8 gallons of water in the tank. After 9 ​hours, 4.4 gallons remain. Write a linear function rule that models the number of gallons of water y left in the tank for any number of hours x. The linear function rule is y = ___

Answer 1

`y=-0.4x+8`

Explanation:

Let the Linear Function to represent the drip of water out of the water tank be:

`y=mx+c`

Where
`x` is the time

`y` is the number of gallons at that time

`m` is the rate at which water drips

`c` is the initial number of gallons of water in the tank

Putting the given values in the above equation:

`6.8 = m* 3+c ..... (1)`

`4.4 =m* 9+c..... (2)`

Subtracting (1) from (2):

`6m=-2.4\\\Rightarrow m =-0.4`

Putting in equation (1):

`6.8=-0.4* 3+c\\\Rightarrow c = 8`

Therefore, the linear function equation to represent in the situation is:

`y=-0.4x+8`