Answer : 76 gallons of oil would have been released after the first 6 hours
The total gallons of oil is = 108, 000 galllons
The total volumes of oil = 108, 000
For every 2 hours = 1/3 of the main volume will be removed
For the first 2 hours
1/3 x total volumes
1/3 x 108, 000
108, 000 / 3
= 36, 000
The remaining volume = 108, 000 - 36, 000
The remaining volume = 72, 000
For the second 2 hours
1/3 x remaining volume
1/3 x 72000
72000/3
= 24, 000
The remaining volume after 4 hours = 72,000 - 24, 000
The remaining volume = 48, 0000
For the third 2 hours
1/3 x 48, 000
48, 000/3
16, 000
Total volumes released after 6 hours is
36, 000 + 24, 000 + 16, 000
Total volume released = 76, 000 gallons
Therefore, 76 gallons of oil would have been released after the first 6 hours