Water tank problem

Question

a tank contains 10000 gallons of water. each week 500 gallons of water evaporates from the tank. water sells for $0.50 a gallon now and the price of the water increases by 5 cents a week. in dollars what would the value of the water in the tank be x weeks from now?

Answer 1

The price of the water can be calculated by (price per gallon) *( number of gallons)

 

So if x is the number of weeks, you need to calculate these 2 quantities.

 

The price is ......$.50  + $.05x  per gallon.

The number of gallons is 10000 - 500x

 

You should check with all representations. After week 1, the price would be .55 and the number of gallons would be 9500.

 

Since the representation is giving me the numbers I want, the number of dollars each week would be represented by

(.50 + .05x)*(10000 - 500x)

 

Hope this helped.