Difference between revisions of "2021 JMPSC Sprint Problems/Problem 5"
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-OofPirate | -OofPirate | ||
− | + | == Solution 2 == | |
+ | The number must have digits <math>8</math> and <math>9</math>. <math>89</math> is odd but <math>\boxed{98}</math> is even. | ||
==See also== | ==See also== |
Revision as of 09:35, 12 July 2021
Contents
[hide]Problem
What two-digit even number has digits that sum to ?
Solution
There exists a digit even number that has digits that sum to
. Pertaining to the assumption that this operation is in base
, there exists only
digits to be used, specifically only
for the first digit. Only
and
may be used, as there isn't other pair of digits which sum to
The only two numbers in which satisfy the fact that the digits sum to are
and
. Yet, only
works because it is the only one in which satisfies the condition that the number must be even.
Therefore, is the only two-digit even number that has digits that sum to
.
-OofPirate
Solution 2
The number must have digits and
.
is odd but
is even.
See also
The problems on this page are copyrighted by the Junior Mathematicians' Problem Solving Competition.