I read an article in the local newspaper about the number of wildlife that is killed in our National Parks (mostly by motorists who are speeding).   The article stated, "In Grand Teton National Park in Wyoming, the number of large mammals (weighing more than 30 pounds) killed in vehicle collisions climbed 205% from 1991 to 2011."   I searched on the internet and found that 203 animals were killed in Grand Teton National Park in 2011.

How many animals were killed in Grand Teton National Park in 1991?



Solution to the Problem:

The answer is: 67

Let x = number of animals killed in 1991.
Then   x + 2.05x = 203
Then   3.05x = 203
So   x = 66.557 or 67.

James Alarie added the following commentary about the problem...

If the article had said that the number had climbed 10%, it would mean that the same number PLUS 10% of that base number had died. For "climbed 205%", it should mean that the same number plus 205% of the base number had died. I could then divide 203 by (1 + 2.05) and find that the number for 1991 was 66.55. What happened to the .55 animal? Did he get revived and then die later? The result should be an integer.

If I assume that the 1991 number was 66, then the climb would be 207.5%. That's too high to "round off" to 205% unless someone is being very liberal in the round-off department. If the 1991 number were 67, then the climb would be 203%; that's too low.

It appears to me that the newspaper article misstated the "climb" number. A 1991 number of 99 gives a ratio of 205%, so that sounds likely.

Correctly solved by:

1. Lisa Merwyn Taylor, Michigan
2. James Alarie Flint, Michigan
3. Chad Fore Gate City, Virginia
4. Mishan Kasipsarsad Johannesburg, South Africa