Answer:
22
Step-by-step explanation:
21.6 would round up because 6 is closer to 10 than it is 0
The answer is 29/34 your answer
To fill:
6 hours = 1 tank
1 hour = 1/6 tank
To drain:
It takes 4 times as long, therefore 4 x 6 = 24
24 hours = 1 tank
1hour = 1/24 tank
If both pipes are open
1 hour = 1/6 - 1/24 = 1/8 tank
1/8 tank = 1 hour
8/8 tank = 1 x 8 hour
1full tank = 8 hours
