28 September 1998
Independent Mathematical Contractors, Inc.
Suite 2, Strawmarket Business Plaza
Lonlinc, SK 04685
Dear IMC:
Our great thanks for your prompt and useful work on the matter of the acid rain that we are hoping not to suffer from in Lonlinc. We have forwarded your report to the various agencies of import to which we inevitably report, and have received numerous accolades therefrom as a result of its comprehensive assessment of the problem. As a result of this report, however, we have received a reply from the transportation division of the Lonlinc bureaucracy. It appears that they are in the process of installing some high-gain solar panels to power a number of traffic direction devices about the city, the surfaces of which will eventually become pitted and therefore less clear as they are exposed to the acidity of the precipitation. According to their estimates, it would take exposure to an amount of Nitric Acid (NO3) equal to 800 grams for this to have a significant impact on the solar panels' electrical yield.
We therefore need to know, based on the data for monthly precipitation and NO3 concentration reproduced in tables 1 and 2 below, at what point the total acidic exposure to which a solar panel will have been subjected will equal or exceed 800 g of NO3.
It is with great pleasure that we anticipate your final report of 3--6 pages on this matter, which we need to receive by the 2nd of November. Owing to the success of the secondary consulting arrangment implemented with your previous project work, we have again made our scientific expert, Dr. Gavin LaRose, available to answer any questions that you might have in the course of your investigation. Again, he will unfortunately be unavailable to assist on this project over the weekend of 31 October--1 November. You should with your project team also plan on meeting with him sometime in the week of the 19th of September.
Sincerely
Jack C. Ousteaux
Director, Lonlinc CPE
jco:glr
Table 1: Average monthly precipitation (mm)
| month | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 |
| avg precipitation | 17.3 | 20.6 | 60.0 | 70.5 | 109.8 | 114.0 | 99.9 | 98.7 | 101.6 | 62.3 | 35.1 | 26.0 |
| month | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 |
| avg. precipitation | 17.7 | 21.8 | 59.6 | 75.0 | 110.9 | 108.8 | 100.4 | 102.8 | 96.5 | 59.3 | 36.9 | 25.5 |
| month | 25 | 26 | 27 | 28 | 29 | 30 | 31 | 32 | 33 | 34 | 35 | 36 |
| avg. precipitation | 17.3 | 20.9 | 56.7 | 13.4 | 108.9 | 105.5 | 92.8 | 103.3 | 98.3 | 60.9 | 53.9 | 25.1 |
Table 2: Average NO3 concentration in precipitation (g/ml)
| month | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 |
| NO3 conc. | 0.4003 | 0.4033 | 0.4060 | 0.4078 | 0.4100 | 0.4124 | 0.4136 | 0.4171 | 0.4184 |
| month | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | NO3 conc. | 0.4214 | 0.4248 | 0.4255 | 0.4282 | 0.4307 | 0.4331 | 0.4356 | 0.4380 | 0.4409 |
| month | 19 | 20 | 21 | 22 | 23 | 24 | 25 | 26 | 27 | NO3 conc. | 0.4440 | 0.4454 | 0.4490 | 0.4513 | 0.4532 | 0.4567 | 0.4587 | 0.4603 | 0.4638 |
| month | 28 | 29 | 30 | 31 | 32 | 33 | 34 | 35 | 36 |
| NO3 conc. | 0.4658 | 0.4700 | 0.4715 | 0.4743 | 0.4772 | 0.4805 | 0.4834 | 0.4852 | 0.4879 |