Author Topic: Brain Teaser (Read 1456 times)

etat · « **on:** June 03, 2004, 12:19:57 pm »

Take a break and sharpen yor math skills
I started two watches at the same time. It turned out that
one of them went two minutes per hour too slow,
and the other went one minute per hour too fast. When I looked at them again, the faster one was exactly one hour ahead of the other. How long had the watches been running?

Mark M · « **Reply #1 on:** June 03, 2004, 12:42:41 pm »

I'm thinking 20 hours but there must be a trick cause that's too easy.

iain · « **Reply #2 on:** June 03, 2004, 12:55:05 pm »

when did you buy them?

Danny_S · « **Reply #3 on:** June 03, 2004, 01:07:28 pm »

Ummmmm yea, I'm with mark,.... 20 hrs. Do I win a FF hat

etat · « **Reply #4 on:** June 03, 2004, 03:49:22 pm »

20 hours it is. The WINNERS are eligible to enter the Logerite contest!!!! Additionally, I'll send ya a big ole box of grits!!!!!

Ummm Good!!!!

Rocky_J · « **Reply #5 on:** June 03, 2004, 04:27:53 pm »

ummmm, 17 hours?

Tom · « **Reply #6 on:** June 03, 2004, 04:54:14 pm »

I've been figgerin' on this thing for about 2 hours now and still need some more time. My watchs are those 3 minute egg timers and I took some sand out of one and put it in the other and been turnin'em over real regular. If I don't lose count it'll still be awhile. :-/

SwampDonkey · « **Reply #7 on:** June 03, 2004, 06:47:13 pm »

hmmm
X = number of minutes running

X/60 = 60 - 2X/60
X = 3600 - 2X
3X = 3600
X = 1200 minutes = 20 hrs

ARKANSAWYER · « **Reply #8 on:** June 03, 2004, 08:15:37 pm »

YEP! That was easy. Now when are the two watches going to have the same right time again? I bet not before my Wife takes them both back to Wal Mart.

ARKANSAWYER
Remember even a broken watch is right twice a day.

OneWithWood · « **Reply #9 on:** June 04, 2004, 08:51:20 am »

Some days the broken watch does better than me

Tom · « **Reply #10 on:** June 04, 2004, 11:16:23 am »

I lost count of the egg timers. Had to start over..... I quit

etat · « **Reply #11 on:** June 04, 2004, 02:28:41 pm »

etat · « **Reply #12 on:** June 04, 2004, 03:22:21 pm »

Ok here's ya another one.
How many feet in a mile. Hint (5280 feet). Why?

?

Rocky_J · « **Reply #13 on:** June 04, 2004, 03:27:00 pm »

ummm..... 5280?

Tom · « **Reply #14 on:** June 04, 2004, 03:48:15 pm »

Because the mille (roman mile) was comprised of 5,000 feet.(real feet)

The English used furlongs (660 feet)

For the English to use miles, they had to change the Mile's length to 8 furlongs (5,280 real feet) so it would match their system of surveying farm land which, was measured in furlongs.

The Statute mile is 8 furlongs, 80 chains, 320 rods, 1760 yards or 5280 feet or, if you are from one of those Metric countries, exactly 1609.344 meters.

Now, if you are talking about Nautical miles?

10 cables = 1 nautical mile = 6080 feet = the angular distance of 1 minute of arc on the earth's surface

:-/.

http://www.gwydir.demon.co.uk/jo/units/sea.htm

SwampDonkey · « **Reply #15 on:** June 04, 2004, 05:34:45 pm »

Here's one fer ya's

How many square miles does an aerial photograph, with a scale of 1 inch = 1040 feet, cover ( 1 cm = 12500 cm, metric). Format of the photo is 9 inches by 9 inches.

[Edit]
Solution: 1 inch/1040 feet = X/9 inch
X = 9360 feet
so, 9360feet/5840 feet/mile = 1.60 mile
square that = 2.56 square miles

Note that most aerial photos have 30 % overlap for stereo and if you discount this area on the photo you have 1 square mile toward the centre of the photo without overlap.

[snip]

Here's another one, carefull its loaded

Assume that two road intersections shown on a photograph can be located on a 1:25,000 scale topographic map. If the measured distance between the intersections is 47.2 mm on a map and 94.3 mm on the photograph, (a) What is the scale of the photograph? (b) At that scale, what is the length of a fence line which measures 42.9 mm on the photograph? AND (c) Is the scale in reference to sea level or terrain elevation?

[Edit]

a) ground distance between the intersection is determined from the map scale as:

0.0472 m x 25,000/1 = 1180 m
1
by direct ratio, the photo scale is:
= 0.0943 m/1180 m = 1/12,513 or 1: 12,500 ( 3 sign. figures)

b) 0.0429 m / 1/12,500 = 536.25 m or 536 m

c) this case its in reference to sea level because measurements were compared with an assumed map datum (height above sea level).

Note: If we took measurements on the ground by measuring the horizontal distance between intersections and compared it to the measured distance on the photo, we would be determining scale in relation to terrain elevation. Don't even need to know the height of the camera lens above sea level in that case. This is called ground truthing the aerial photograph. If you know the height above sea level the camera was when taking the photo then you can determine terrain elevation. Some cameras will record the altitude and stamp it on each photo, taken from the planes instruments.

Simple stuff, right?

[snip]

Tom · « **Reply #16 on:** June 04, 2004, 06:16:08 pm »

hmm-m I need a metric egg timer :-/

Danny_S · « **Reply #17 on:** June 04, 2004, 06:56:09 pm »

-------ALOT------

Rocky_J · « **Reply #18 on:** June 04, 2004, 07:15:25 pm »

ummmm... I GOT IT!!!
20 hours!

etat · « **Reply #19 on:** June 04, 2004, 10:33:48 pm »

Tom, great answer!!!!

Swamp, that's a trick question. We gotta know the altitude the pictures were taken from, what kinda camera, the exact geographic location of the map, the method used to develope the film, the property owners full name and birthdate, what type of fence, and if the roads are blacktop, concrete, dirt, or gravel, before we can even begin to calculate an answer!!!!

News:

Author Topic: Brain Teaser (Read 1456 times)