Difference between revisions of "2009 AIME II Problems/Problem 1"
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We know that all the stripes are of equal size. We can then say that <math>r</math> is the amount of paint per stripe. Then <math>130 - r</math> will be the amount of blue paint left. Now for the other two stripes. The amount of white paint left after the white stripe and the amount of red paint left after the blue stripe are <math>188 - r</math> and <math>164 - r</math> respectively. The pink stripe is also r ounces of paint, but let there be <math>k</math> ounces of red paint in the mixture and <math>r - k</math> ounces of white paint. We now have two equations: <math>164 - r - k = 188 - r - (r-k)</math> and <math>164 - r - k = 130 - r</math>. Solving yields k = 34 and r = 92. We now see that there will be <math>130 - 92 = 38</math> ounces of paint left in each can. <math>38 * 3 = \boxed{114}</math> | We know that all the stripes are of equal size. We can then say that <math>r</math> is the amount of paint per stripe. Then <math>130 - r</math> will be the amount of blue paint left. Now for the other two stripes. The amount of white paint left after the white stripe and the amount of red paint left after the blue stripe are <math>188 - r</math> and <math>164 - r</math> respectively. The pink stripe is also r ounces of paint, but let there be <math>k</math> ounces of red paint in the mixture and <math>r - k</math> ounces of white paint. We now have two equations: <math>164 - r - k = 188 - r - (r-k)</math> and <math>164 - r - k = 130 - r</math>. Solving yields k = 34 and r = 92. We now see that there will be <math>130 - 92 = 38</math> ounces of paint left in each can. <math>38 * 3 = \boxed{114}</math> | ||
− | === Solution | + | === Solution 4 === |
Let the amount of paint each stripe painted used be <math>x</math>. Also, let the amount of paint of each color left be <math>y</math>. 1 stripe is drawn with the blue paint, and 3 stripes are drawn with the red and white paints. Add together the amount of red and white paint, <math>164 + 188 = 352</math> and obtain the following equations : <math>352 - 3x = 2y</math> and <math>130 - x = y</math>. Solve to obtain <math>x = 92</math>. Therefore <math>y</math> is <math>130 - 92 = 38</math>, with three cans of equal amount of paint, the answer is <math>38 * 3 = \boxed{114}</math>. | Let the amount of paint each stripe painted used be <math>x</math>. Also, let the amount of paint of each color left be <math>y</math>. 1 stripe is drawn with the blue paint, and 3 stripes are drawn with the red and white paints. Add together the amount of red and white paint, <math>164 + 188 = 352</math> and obtain the following equations : <math>352 - 3x = 2y</math> and <math>130 - x = y</math>. Solve to obtain <math>x = 92</math>. Therefore <math>y</math> is <math>130 - 92 = 38</math>, with three cans of equal amount of paint, the answer is <math>38 * 3 = \boxed{114}</math>. |
Revision as of 04:08, 16 January 2022
Contents
Problem
Before starting to paint, Bill had ounces of blue paint,
ounces of red paint, and
ounces of white paint. Bill painted four equally sized stripes on a wall, making a blue stripe, a red stripe, a white stripe, and a pink stripe. Pink is a mixture of red and white, not necessarily in equal amounts. When Bill finished, he had equal amounts of blue, red, and white paint left. Find the total number of ounces of paint Bill had left.
Solution 1 (Simple Solution)
Let the stripes be and
, respectively. Let the red part of the pink be
and the white part be
for
.
Since the stripes are of equal size, we have . Since the amounts of paint end equal, we have
. Thus, we know that
Each paint must end with
oz left, for a total of
oz.
Solution 2
After the pink stripe is drawn, all three colors will be used equally so the pink stripe must bring the amount of red and white paint down to ounces each. Say
is the fraction of the pink paint that is red paint and
is the size of each stripe. Then equations can be written:
and
. The second equation becomes
and substituting the first equation into this one we get
so
. The amount of each color left over at the end is thus
and
.
Solution 3
We know that all the stripes are of equal size. We can then say that is the amount of paint per stripe. Then
will be the amount of blue paint left. Now for the other two stripes. The amount of white paint left after the white stripe and the amount of red paint left after the blue stripe are
and
respectively. The pink stripe is also r ounces of paint, but let there be
ounces of red paint in the mixture and
ounces of white paint. We now have two equations:
and
. Solving yields k = 34 and r = 92. We now see that there will be
ounces of paint left in each can.
Solution 4
Let the amount of paint each stripe painted used be . Also, let the amount of paint of each color left be
. 1 stripe is drawn with the blue paint, and 3 stripes are drawn with the red and white paints. Add together the amount of red and white paint,
and obtain the following equations :
and
. Solve to obtain
. Therefore
is
, with three cans of equal amount of paint, the answer is
.
Solution 4
Let be the number of ounces of paint needed for a single stripe. We know that in the end, the total amount of red and white paint will equal double the amount of blue paint.
After painting, the amount of red and white paint remaining is equal to , and then minus another
for the pink stripe. The amount of blue paint remaining is equal to
.
So, we get the equation
. Simplifying, we get
and
.
~LegionOfAvatars
Solution 5
Just like in solution 1, we note that all colors will be used equally, except for the pink stripe. This must bring red and white down to each, so
red and
white are used, making for a total of
for the pink stripe. Thus, the other stripes also use
. The answer is
= See Also
2009 AIME II (Problems • Answer Key • Resources) | ||
Preceded by First Question |
Followed by Problem 2 | |
1 • 2 • 3 • 4 • 5 • 6 • 7 • 8 • 9 • 10 • 11 • 12 • 13 • 14 • 15 | ||
All AIME Problems and Solutions |
The problems on this page are copyrighted by the Mathematical Association of America's American Mathematics Competitions.