An outdoor storage bin contains 15,000 kilograms of road salt. Each day, a quarter of the salt is removed. How much salt is in the bin at the end of the 18th day?

Question

anonymous · Answer

your just going to have to divide 15,000 into 4 then multiply by three and repeat the same process 17 more times

anonymous · Answer

Why would I divide by 4? Why would I multiply it by 3?
The way I was doing it is I multiplied 15,000 by .25 and got 3,750. So, I subtracted that from 15,000 and got 11,250.
Then I multiplied 11,250 by .25 and got 2,812.5. So, I subtracted that from 11,250 and got 8,437.5.
I would keep doing that until I reached 18, but that would take way too long.
I'm not even sure if I'm doing it correctly.

anonymous · Answer

It's much easier just to divide and multiply and the answer is more certain the correct answer is 63.4242399

anonymous · Answer

Okay, thank you.

anonymous · Answer

Anytime :)

wolf1728 · Answer

blueberry520
Basically, this should be approached like a "half life" problem.
The difference here is that for every day, the amount remaining is one quarter (instead of one half).
So, the remaining amount equals:
15,000 *(.75^t) where 't' is the time in days.
So after 2 days the amount remaining is
15,000*(.75^2)=
15,000*0.5625 which equals
8,437.50 after 2 days

After 3 days, the amount remaining 
15,000*(.75^3)=
15,000*0.421875 which equals
6,328.125

So, at the end of the eighteenth day the amount remaining equals
15,000*(.75^18)=
15,000*0.0056377101136604 which equals
84.5656517049 kilograms

By the way, Shelby's answer is correct for the NINETEENTH day.
Mine is correct for the 18 days.