precal nightmare
posted by Anonymous on .
Suppose a U.S. presidential candidate announced that, if elected, he would create a national park out of trash. For a period of one year, all residential and commercial trash usually sent to landfills would be trucked to a central spot. Over time, the trash would spread out in an everwidening circle to a thickness of 3 feet. The latest scientific methods would be applied to convert the trash to playgrounds and picnic areas. The candidate also promised to reside at the center of the park. (don't know if that's relevant)
The candidate's environmental policy committee found that 60% of American trash is residential, while 40% is commercial. Four hundred and twentyfive pounds of residential trash occupy one cubic yard; whereas 375 pounds of commercial trash occupy one cubic yard.The total amount of trash dumped per day is 570,000 tons. find the total volume of commercial plus resid

There are 0.60x570,000 = 342,000 tons = 6.84*10^8 lb per day of residential trash, occupying 1.609*10^6 cubic yards.
There are 0.40*570,000 = 228,000 tons = 4.56*10^8 lb per day of commercial trash, occupying 1.216*10^6 cubic yard.
Total cubic yards per day = 2.825*10^6 cubic yards.
Multiply this by 365 days for the volume deposited in a year. I get 1.616*10^9 cubic yards.
The area will be 1.616*10^9 square yards, since it is a yard thick.
The radius will be 22704 yards, or 12.89 miles. 
It's a multiple choice, those aren't one of the options. I'm not understanding where you got some of your numbers. Should 342,000 and 228,000 be divided by 425 to get the cubic yards?

The two types of garbage get divided by different densities to get volumes.
The problem may be that the 60/40 ratio applies to volumes and not weights. That would require a different method. They should have said which it is.
I also could have made a math error. It happens.