Answer:
Option d.
Step-by-step explanation:
Number of family members = 5
Average time for shower = 8 minute per member
Time period = 30
Initial rate of water = 5-gallon-per-minute
Initial use of water is
[tex]5\times 8\times 30\times 5=6000[/tex]
New rate of water = 2-gallon-per-minute
Use of water after new shower is
[tex]5\times 8\times 30\times 2=2400[/tex]
Difference between use of water is
[tex]6000-2400=3600[/tex]
It means the family will use 3600 fewer gallons of water with the new shower heads.
Therefore, the correct option is d.