Country - Amount Recycled, amount not recycled

[tylderdurden]

Country Amount Recycled, Amount not recycled
a - 16,700 - 142,800
b - 8,800 - 48,000
c - 13,000 - 51,400
d - 3,900 - 20,300
e - 3,300 - 16,200

Which country had the lowest ratio of waste material disposed of to waste material recycled each year?

Ok, I know that I could brute force this in a test, but I'd much rather not as it took me a good 10 minutes on my practice exam... how would one go about estimating the numbers?

[krusta80]

Country Amount Recycled, Amount not recycled
a - 16,700 - 142,800
b - 8,800 - 48,000
c - 13,000 - 51,400
d - 3,900 - 20,300
e - 3,300 - 16,200

Which country had the lowest ratio of waste material disposed of to waste material recycled each year?

Ok, I know that I could brute force this in a test, but I'd much rather not as it took me a good 10 minutes on my practice exam... how would one go about estimating the numbers?

Sometimes you need to do some number crunching, but there is a way to attack this without working out the division to the decimal point. In fact, you don't really need to divide at all (depending on how close the estimates are to eachother).

Instead, figure out between which two integers each ratio is. Watch...

a - 16,700 - 142,800

16,700*9 ~= 144,000, which is just slightly bigger than 142,800

So, it's between 8 and 9. Moving on...


b - 8,800 - 48,000

8,800*6 ~= 48,000, but it's bigger, so we're between 5 and 6.


c - 13,000 - 51,400

13000*4 = 52000, which is bigger than 51,400, so we're between 3 and 4.


d - 3,900 - 20,300

3,900*5 ~= 20,300, but it is smaller, so we're between 5 and 6.


e - 3,300 - 16,200

3,300*5 = 16,500, which is bigger, so we're between 4 and 5.


There is no need to get any more precise, since only C is between 3 and 4.

C it is.

[m_mkumar]

Good work. Keep it up man!!