High School Math

MISSION STATEMENT: To encourage and promote a greater use of the internet and computer technology in the math classroom. For educators, students, parents and homeschoolers.

Saturday, April 09, 2005

Money!


A class contributed $3.50 in nickels
and dimes for the Tsunami Relief Fund.
In all there were 45 coins.
How many were there of each kind?
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How Old?


Ray is 20 years older than Bill.
Five years ago, Ray was 5 times
as old as Bill was then. Find the
present age of both Ray and Bill.
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Sunday, April 03, 2005

Stamps

Cynthia purchased almost 100 stamps today, in three different lots.
Some of her stamps cost 66 cents, some cost $1.68, and some cost $3.08.
She paid exactly the same amount for each lot.
How much did she pay for each lot?
 One possible solution is :
Let the number of stamps in each lot be x, y, z.
Then 66x = 168y = 308z
Factors of 66 are 2x3x11
of 168 are 2x2x2x3x7
of 308 are 2x2x7x11
Common factors of the three are 2x2x2x3x7x11 = 1848
Thus, 66x = 1848k, 168y = 1848k, 308z = 1848k where k is an integer.
Then x = 28k, y = 11k, z = 6k.
Now, x + y + z = 45k.
And, since the number of stamps is almost 100, k must be equal to 2.
Number of stamps in first lot is x = 28x2 = 56.
in second lot is y = 11x2 = 22.
in third lot is z = 6x2 = 12.
Total number of stamps is 56+22+12 = 90.
Value of stamps in first lot is 66x56 = $36.96.
in second lot is 168x22 = $36.96.
in third lot is 308x12 = $36.96.
If you have a shorter solution please submit as guest or comment.

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puzzle, amusement, enrichment or challenge question
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Super Fork!


Look at this trident fork carefully for one minute.
Then draw it from memory. If you can draw it correctly
without referring back to this drawing more than twice, then you surely have a photographic memory.
Leave me a private message on my guest book
or post a general comment for everyone.

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puzzle, amusement, enrichment or challenge question
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Special Number

Tom has a very special four digit number.
To divide it by 7, you only had to drop its second digit.
What is the number?

An acceptable solution might be :
Let first digit be x,
second digit be y,
and third and fourth digits be z.
The number is 1000x + 100y +z.
Dropping the second digit gives value as 100x + z.
So, 1000x + 100y + z = 7(100x + z).
Or, 150x + 50y = 3z.
Since 50 is common on the left, and z is 2 digits, let z=50.
Then 3x + y = 3.
Since x is not zero, let us assume x=1, then y=0.
So the number is 1050.

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puzzle, amusement, enrichment or challenge question
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Leaflets

An advertizing company had 3000 leaflets printed.
The executive in charge could not remember how many they mailed last year. However, she did remember that there was always one over when she divided the number of leaflets mailed, by any number from 2 through 9.
How many leaflets were mailed last year?

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Five Kids

Matilda has 5 kids, with a girl in the middle.
They are all spaced 2 years apart.
The youngest boy is just half as old as the oldest.
How old is the girl?

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puzzle, amusement, enrichment or challenge question
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Friday, April 01, 2005

Three Guys

Doug, Ken and Joe are partners.
One has a beard.
Two are married.
Two have blue eyes.
Two are clean-shaven.
The bearded one has brown eyes.
Doug's wife is Ken's sister.
The bachelor has the same colour eyes as Joe.
Who has the beard?

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puzzle, amusement, enrichment or challenge question
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Fence

Doug put up a fence at the end of the lawn.
He planned to have the posts 5 feet apart.
He found that he was 4 posts short.
So he had to place the posts 7 feet apart to do the job.
How long was his fence to be?

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puzzle, amusement, enrichment or challenge question
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Lumberjack

Said a feller out felling a tree,
"My age I've divided by three.
The result is a square,
Yet my age, I declare,
Is six times a cube. Glory be!"

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puzzle, amusement, enrichment or challenge question
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