Amount of work Peter can do in an hour = (1/20)

Amount of work Quagmire can do in an hour = (1/5)

Let Goldman is able to complete one piece of work in 'n' hours,

⇒ Then the amount of work Goldman does in an hour = 1/n

⇒ Thus, total work done by all 3 in an hour = (1/20) + (1/5) + (1/n)

⇒ Total amount of work done by all 3 in a couple of hours (2 hours) = {(1/20) + (1/5) + (1/n)} × 2       ---- (1)

From given data,

The entire piece of work is completed in 2 hours.

⇒ {(1/20) + (1/5) + (1/n)} × 2 = 1

⇒ {(1/20) + (1/5) + (1/n)} = ½

⇒ (1/n) = ½ – {(1/20) + (1/5)}

⇒ (1/n) = ½ – (5/20)

⇒ (1/n) = ¼

As Goldman does 1/4^th of the work in an hour.

⇒ They finished the work in 2 hours

Therefore, part of the work done by Goldman = 2 × ¼ = ½

∴ He gets ½ × 1008 = $504