A leaky value on the water meter overcharges the residents for one gallon of water every 1 1/3 months. The overcharged amount w varies directly with time t find the equation that models this direct variation how many months it will take for the residents to be overcharged for 9 gallons of water?

4/3 months/ gallon or 1 gallon/ (4/3) months is 3/4 gallons/month

w = ( 3/4 ) * t
t is in months , w in gallons
9 =(3/4) t
3 = t/4
t = 12 months which is one year.

To model the direct variation between the overcharged amount (w) and time (t), we can use the formula:

w = kt,

where k is the constant of variation.

We know that the residents are overcharged for one gallon of water every 1 1/3 months. To find the value of k, we need to determine how many gallons of water are overcharged in that time period.

Let's convert the time of 1 1/3 months into a mixed number fraction:
1 1/3 months = 4/3 months

Now, we can set up a proportion to find the value of k. Since the residents are overcharged by 1 gallon of water in 4/3 months:

1 gallon / (4/3 months) = k gallons / t months

To simplify the proportion, we divide 1 by 4/3:

1 ÷ (4/3) = 3/4

So, the proportion becomes:

3/4 = k/t

Now, we need to find the value of k in terms of t. We can rearrange the equation to do that:

k = (3/4)t

Therefore, the equation that models the direct variation between the overcharged amount (w) and time (t) is:

w = (3/4)t

To find the number of months it will take for the residents to be overcharged for 9 gallons of water, we can substitute w = 9 into the equation:

9 = (3/4)t

Now, we can solve for t:

(3/4)t = 9

Multiply both sides of the equation by 4/3 to isolate t:

t = (9 × 4/3)

Simplifying, we have:

t = 12

Therefore, it will take the residents 12 months to be overcharged for 9 gallons of water.