Answer: 24 hours
Explanation:
Let x represent the number of hours that Jerry worked, then:
Jerry: x
Jeff: 2x
Paul: 2x + 6
Jerry + Jeff + Paul = Total
x + 2x + 2x + 6 = 51
5x + 6 = 51
5x = 45
x = 9
Jerry: x --> 9
Jeff: 2x --> 2(9) = 18
Paul: 2x + 6 --> 2(9) + 6 = 24