Difference between revisions of "2015 AMC 10B Problems/Problem 25"
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Thus, our answer is <math>\boxed{\textbf{(B)}\;10}</math> | Thus, our answer is <math>\boxed{\textbf{(B)}\;10}</math> | ||
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+ | ==Simplification of Solution== | ||
==See Also== | ==See Also== |
Revision as of 14:29, 23 September 2017
Problem
A rectangular box measures , where
,
, and
are integers and
. The volume and the surface area of the box are numerically equal. How many ordered triples
are possible?
Solution
The surface area is , the volume is
, so
.
Divide both sides by , we get that
First consider the bound of the variable . Since
we have
, or
.
Also note that , we have
.
Thus,
, so
.
So we have or
.
Before the casework, let's consider the possible range for if
.
From , we have
. From
, we have
. Thus
When ,
, so
. The solutions we find are
, for a total of
solutions.
When ,
, so
. The solutions we find are
, for a total of
solutions.
When ,
, so
. The only solution in this case is
.
When ,
is forced to be
, and thus
.
Thus, our answer is
Simplification of Solution
See Also
2015 AMC 10B (Problems • Answer Key • Resources) | ||
Preceded by Problem 24 |
Followed by Last Question | |
1 • 2 • 3 • 4 • 5 • 6 • 7 • 8 • 9 • 10 • 11 • 12 • 13 • 14 • 15 • 16 • 17 • 18 • 19 • 20 • 21 • 22 • 23 • 24 • 25 | ||
All AMC 10 Problems and Solutions |
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