Pablo was reviewing the water bill for his carwash business and determined that the highest bill, $5,000, occurred in july when 4,000 cars were washed and the lowest bill, $4,000, occurred in february when 2,000 cars were washed. what was the fixed portion of the water bill?

The easiest way to solve this is to work with two equations:

X + 4000Y = $5000  (1)

X + 2000Y = $4000  (2)

Where X is the fixed portion of the water bill and Y is the cost of water per car.

Solve for X for each equation:

X = $5000 – 4000Y  (3)

X = $4000 – 2000Y  (4)

Therefore:

$5000 – 4000Y = $4000 – 2000Y (5)

Solve for Y:

Y = $0.5

Substitute into equation1:

X + 4000(0.5) = $5000

X = $3000

the first successful, urban blues recording, selling more than 75,000 copies, was made in year 1920.

mamie smith recorded the first commercially successful example of the urban blues,   with the recording of “crazy blues”."crazy blues" was recorded on august 10, 1920, in new york city. within a month of the release of “crazy blues” it had sold 75,000 copies.