Percentages are ratios of an amount compared to 100. The percent change of an old to new value is equal to 100% x \({ new - old \over old }\).
The total water usage for a city is 30,000 gallons each day. Of that total, 28% is for personal use and 50% is for industrial use. How many more gallons of water each day is consumed for industrial use over personal use?
| 9,900 | |
| 750 | |
| 6,600 | |
| 4,500 |