a problem to solve? can you?

[PHiuR]

"you begin to solve a complicated math problem between 4 and 5 PM. when the clock's hour and minute hands are together (on top of each other) you finish the problem when the minute hand is exactly opposite the hour hand.

-how many minutes does it take you to solve the problem?

-at what time do you finish the problem?



lets add this:

round to nearest second.

 

[alkemyst]

Assuming it must be around 4:22-23 when you start and then 4:52-53 when you finish, 30mins.

I just polished off a case, so maybe I am missing something

 

[Legendary]

For every 12 minutes the hour hand moves one minute. So you start at 4:24 and you end at 4:54ish.

 

[HonkeyDonk]

it's gotta be more than 30 min total time, b/c if you think about it as if it were starting at 12 exactly, then when the minute is opposite the hour hand, that's gonna be around 33 min or so.

 

[HonkeyDonk]

Originally posted by: Legendary
For every 12 minutes the hour hand moves one minute. So you start at 4:24 and you end at 4:54ish.

at 4:24, the hour hand/minute hand aren't on top of each other.

 

[PHiuR]

added:

round to nearest second.

this will help.

 

[DrPizza]

simplest way is to solve this is to "straighten" the clock out into a straight line.

First, solve for the starting position. You should be able to figure out the speed of the minute hand and the speed of the hour hand. Final position is when the difference between the two positions is exactly 30 minutes.

 

[PowerEngineer]

I looks to me like it takes 32'43'' to solve the problem (just barely faster myself), and finish at 4:54:32.

 

[DrPizza]

Minute hand moves 6 degrees per minute. Hour hand moves .5 degrees per minute.
Starting at 4:00, solve for x, the number of minutes...

0 degrees + 6x = 120 degrees + .5 x (minute hand is at 120 degrees at 4:00)

x = 120/5.5 = 21.818181818181 minutes after 4:00.

edit: starting time is 21 minutes 49.0909 seconds after 4 o'clock

 

[DrPizza]

Finish time is when the minute hand is 180 degrees past the hour hand....
Again, starting at 4:00, this occurs when

minute's position - 180degrees = hour's position
0 degrees + 6x - 180 = 120 degrees + .5x
x = 300/5.5 = 54.54545454 minutes past the hour.....



54.54545454.... minutes minus 21.8181818181
= 32.727272 minutes elapsed....
= 32 minutes 43.6363636363636363636363636363636363636363636363636363... seconds.

Originally posted by: PHiuR
added:

round to nearest second.

this will help.

Screw you, I didn't need to round it to the nearest second, nor do I see how it would have helped

 

[PHiuR]

Originally posted by: DrPizza
Finish time is when the minute hand is 180 degrees past the hour hand....
Again, starting at 4:00, this occurs when

minute's position - 180degrees = hour's position
0 degrees + 6x - 180 = 120 degrees + .5x
x = 300/5.5 = 54.54545454 minutes past the hour.....



54.54545454.... minutes minus 21.8181818181
= 32.727272 minutes elapsed....
= 32 minutes 43.6363636363636363636363636363636363636363636363636363 seconds.

Screw you, I didn't need to round it to the nearest second.

::claps:: wow..nice.. i diddnt figure it to that...and very organized lol.

 

[DrPizza]

You quoted me before I edited it for tone was just harassing you with the "screw you" comment

 

4:20!

 

[DrPizza]

Tomorrow's the last day before thanksgiving break... that very well may be one of the problems I give my precalculus class as part of a contest.

 

[neilm]

Nice one DrPizza.

 

[PHiuR]

Originally posted by: DrPizza
Tomorrow's the last day before thanksgiving break... that very well may be one of the problems I give my precalculus class as part of a contest.

do you teach at a high school?

 

[DrPizza]

Yep.... days before holiday vacations are pretty much a waste.... choices are: give a test, or do something fun, yet educational. Enough other teachers already give tests.... I don't like loading the kids up.. I'll just review for 2 days after break and give them a test the first week back... then I'm out of synch with the other teachers as far as giving tests... makes it easier on the students.

 

[bleeb]

Originally posted by: SammySon
4:20!

Happy Happy with Holy Ganja!

 

[PHiuR]

Originally posted by: DrPizza
Yep.... days before holiday vacations are pretty much a waste.... choices are: give a test, or do something fun, yet educational. Enough other teachers already give tests.... I don't like loading the kids up.. I'll just review for 2 days after break and give them a test the first week back... then I'm out of synch with the other teachers as far as giving tests... makes it easier on the students.

nice...you are the understanding type of teacher...haha thanks for being a cool teacher...heres a :beer: from a student...