Question

You have been called in by the N & L Railroad to investigate the results of an accident. A railroad car derailed in a rain storm and spilled a load of salt. unfortunately the spill occurred near Newton's Grove, the only remaining region where the rate Calculus Convergensus Tree still grows. There were approximately 1000 trees before the spill, and all 1,000 trees were exposed to the salt. The first workers on the scene have estimated that about 120 of the trees have already died or will die within a year after the accident. It is also known that many trees exposed to the salt may not die immediately but will eventually die.

One of your first tasks is to try to project the future effects of the spill. A scientist has proposed the following hypothesis: that each year the same percentage of trees still alive that were exposed to the salt will die each year as a result of the exposure to the salt.

Investigate this hypothesis, answering the following questions as well as any other questions you feel will shed light on the problem. Assuming the hypothesis is correct:

1. (a) How many trees will die in the second year after the spill?

(b) What is the total number of trees that will have died in the first two years after the spill?

(c) What fraction of the original 1000 trees have died after two years?

Answer 1