Idaho Society of Professional Engineers
Friday Update – 10/20/06
UPCOMING EVENTS:
• October 27, 2006 - PE and PS
Examinations - Boise, Idaho
• October 28, 2006 - FS (aka
LSIT) Examination - Boise, Idaho, Pocatello, Idaho, Moscow, Idaho
• October 28, 2006 - FE (aka EIT)
Examination - Boise, Idaho. Pocatello, Idaho, Moscow, Idaho
• November 14, 2006 -
ISPE Southwest Chapter
Noon Meeting
• February 6 – 10, 2007 –
Idaho Society of Professional Land
Surveyors Conference - Coeur d' Alene Casino - Worley, Idaho
• March 10, 2007 – State
MATHCOUNTS Competition –
Boise State University, Boise
• March 22 & 23, 2007 – ISPE 2007
Annual Meeting – Oxford Suites, Boise
• May 11, 2007 – National
MATHCOUNTS Competition –
Convention Center, Fort Worth, Texas
THE CITY OF POST FALLS NEEDS YOUR HELP!
Please join us during the week of October 24th through October 30th in a
planning "charrette" - a
participatory workshop where citizens, officials and teams of experts produce
guidelines for future growth compatible with Post Falls' long-range goals.
Click here
to find information concerning the upcoming event, along with the tentative
schedule for presentations, focus groups and design sessions.
Thank you and hope to see you there!
MATHCOUNTS PROBLEM OF THE WEEK
Can you solve this MATHCOUNTS problem? The answer will appear in next week's
edition of the Friday Update!
Trip to Ashland, Oregon
The Wong family (Mom, Dad, and their three sons) are planning a trip from
Corvallis, Oregon to Ashland, Oregon to see a Shakespearean play. There are 2
front seats and 3 rear seats in their car. Assuming that either Mom or Dad will
be driving, how many different seating arrangements are there for the family in
the car?
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The distance from Corvallis to Ashland is 220 miles. If no stops are made along
the way, what average speed will need to be maintained to make the trip in
exactly four hours?
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Assume that instead of driving straight through, the following stops are made on
the trip from Corvallis to Ashland.
a. Purchase gas 10 minutes
b. Rest stop 15 minutes
c. Food stop 20 minutes
What average speed will need to be maintained to complete the trip from
Corvallis to Ashland in exactly four hours? Express your answer to the nearest
whole number.
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Assume the maximum legal speed limit in Oregon is 65mph. The Wongs were able to
maintain an average speed of 62 mph. What is the least amount of time, to the
nearest 10 minutes, the Wong family should expect their trip of 220 miles and
the three stops to take? Express your answer in the form of x hours, y minutes
with y < 60.
Answer to last week’s MATHCOUNTS problem:
Calculate the part of a cord a “face cord” is. The pieces of wood are 16 inches
long or (16/48 = 1/3) 1/3 the width of a cord. Solve the proportion 1/3 = x/75
to calculate the cost per full cord. The cost per full cord of firewood from
Woodstove Fuel Company is $225. Calculate the part of a cord a “stove cord” is.
The pieces of wood are 12 inches long or (12/48 = 1/4) 1/4 the width of a cord.
Solve the proportion 1/4 = x/60 to calculate the cost per full cord of wood from
Light and Burn Fuel Company. The cost per full cord of firewood from Light and
Burn Fuel Company is $240. There is a savings of (240 – 225 = 15) $15 per full
cord if the firewood is purchased from Woodstove Fuel Company.
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The number of mill ends needed to fill the container is the product of the
number of mill ends in the width, length and height of the cord container. The
container is 4 feet = 48 inches high. 48 ÷ 2 = 24 mill ends for the height. The
length is 8 feet = 96 inches. 96 ÷ 12 = 8 mill ends for the length. The width is
4 feet = 48 inches. 48 ÷ 4 = 12 mill ends for the width. The number of mill ends
needed to exactly fill the cord container is 12 × 8 × 24 = 2304 mill ends. The
wood fills the entire cord container whose volume is 4 × 8 × 4 = 128 cubic feet.
The wood volume is 128 cubic feet.
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24 logs can be placed in the first row on the 8 foot side (8 ft × 12 in/ft ÷ 4
in/log = 24). 23 logs can be placed in the second row so that each of the logs
in the second row lies in the empty space between two logs in the first row. 24
logs can be placed in the third row and 23 in the fourth row. Continue this
pattern. The distance between the centers of the circular ends of any three logs
that touch each other is 4 inches and the segments connecting the centers form
an equilateral triangle. The height of the equilateral triangle is 2√3 by the
properties of a 30-60-90 right triangle. Let n = the number of rows of logs
above the first row in the stack. The height of the stack of logs can be
expressed as 2 + 2n √3 + 2 ≤ 48. Solving for n, n ≤ 12.7, so n =12. There are a
total of 13 rows. 7 rows have 24 logs (7 × 24 = 168) and 6 rows have 23 logs (6
× 23 = 138). There are 168 + 138 = 306 logs in the front of the stack. The width
of the container is 4 feet or 48 inches. Each log is 12 inches long. The logs
are stacked 4 deep (48 ÷ 12 = 4). The total number of logs is (4 × 306 = 1224)
1224 logs.
If you want to see last week's problem again, click
http://www.mathcounts.org/webarticles/anmviewer.asp?a=912&z=107
Idaho Society of Professional Engineers
PO Box 170239
Boise, ID 83717-0239
208-426-0636
Fax: 208-426-0639
E-Mail: ispe@idahospe.org
Web Site: www.Idahospe.org
Idaho
Society of Professional Engineers
