Answer: it will take 126 hours for 168 gallons of water to leak out of the pool
Explanation:
Water leaked out of the pool at the rate of 8 gallons every six hours. This means that the time it takes for a gallon of water to leak out of the pool would be
6/8 = 0.75 hour
If the rate remains constant, the number of hours that it will take the 168 gallons of water to leak out of the pool would be
0.75 × 168 = 126 hours