Suppose that an elementary school starts a recycling program. After one year, the school has reduced its trash from 144,000 pounds per year to 122,400 pounds per year. Find the percent
decrease in the amount of trash.

15% is reduced

Step-by-step explanation:

I always start by finding what 10% and 5% is, after that, I try to see how I can make that into the number subtracted and for this it happened to be 15% I found that 10% was 14,400 and 5% was 7,200 and I found the total amount reduced was 21,600 which is 14,400+7,200 or 10%+5%

step-by-step explanation:

12: 00 p.m. to 7: 00 p.m. is a total of 7 hours.

4: 00 p.m. to 7: 00 p.m. is a total of 3 hours.

this means that from 4: 00 p.m to 7: 00 p.m. this represents 3/7 of what was lost from 12: 00 p.m. to 7: 00 p.m.

after knowing this, after doing 11,600 - 6,800 = 4,800

4,800 represents 3/7 of what was lost for 7 hours.

we then divide 4,800 by 3 which gets 1,600.

because we know that 1,600 represents 1/7 of how much water was lost, we just have to multiply by 7, which gets 11,200.   after adding 11,200 to how much water was left at 7: 00 p.m. which was 6,800. 11,200 + 6,800 = 18,000

this means that the pool originally had 18,000 gallons in the pool.

you can also check your work by doing 18,000 - 4(1600), which becomes           1800 - 6400 which gets you 11,600.