In one study, the daily use of toilet flushes is 9.1 gallons of water per person per day.
in new york city, water costs $7.64 per 100 cubic feet of water. calculate the annual cost of toilet flushes for a family of four.
recall that 7.48 gallons = 1 cubic foot, and assume there are 365 days in a year.

$135.70

Step-by-step explanation:

First step is to calculate the daily consumption for this family of four.  We'll assume they're all in age to use and flush the toilet themselves (no babies).

So, one person flushes 9.1 gallons a day, a family of 4 would then flush 4 times that:

daily family flushes = 9.1 gal/person * 4 persons/family = 36.4 gal/family

That's for one day... now for a year...

yearly = 36.4 gal/day * 365 days/yr = 13 286 gal/year

Let's convert those gallons into cubic feet:

13 286 gal / 7.48 gal/ft³ = 1,776.2 ft³

Then we multiply the gallons by the price for 100 cubic feet and divide by 100:

1,776.2  ft³ * $7.64 /100 ft³ = $135.70

the direct variation says that:

then the equation is of the form is given by:

            where k is the constant variation.

from the given table:

consider any value of x and m(x)=y

x = 2 and m(x)=y = 3

substitute these value in [1]; we have;

divide both sides by 2 we get;

⇒

check:

put x = -1 and m(x) = -1.5

substitute in the equation:

-1.5 = -1.5                   true

therefore, the function m(x) represents a direct variation

graph of this function as shown below:

step-by-step explanation: