This preview shows page 1. Sign up to view the full content.
15
2.32
(I saw this problem in John Bentley’s Programming Pearls.) Approach 1:
The model is Depth X Width X Flow where Depth and Width are in miles
and Flow is in miles/day. The Mississippi river at its mouth is about 1/4 mile
wide and 100 feet (1/50 mile) deep, with a
f
ow of around 15 miles/hour
=
360 miles/day. Thus, the
f
ow is about 2 cubic miles/day.
Approach 2: What goes out must equal what goes in. The model is Area X
Rainfall where Area is in square miles and Rainfall is in (linear) miles/day.
The Mississipi watershed is about 1000 X 1000 miles, and the average rainfal
is about 40 inches/year
≈
.1 inches/day
≈
.000002 miles/day (2 X
10
−
6
).
Thus, the
f
ow is about 2 cubic miles/day.
2.33
Note that the student should NOT be providing answers that look like they
were done using a calculator. This is supposed to be an exercise in estima
tion!
The amount of the mortgage is irrelevant, since this is a question about rates.
However, to give some numbers to help you visualize the problem, pick a
This is the end of the preview. Sign up
to
access the rest of the document.
This note was uploaded on 12/27/2011 for the course MAP 2302 taught by Professor Bell,d during the Fall '08 term at UNF.
 Fall '08
 BELL,D

Click to edit the document details