2025 AMC 10A Problems/Problem 8
Agnes writes the following four statements on a blank piece of paper.
At least one of these statements is true.
At least two of these statements are true.
At least two of these statements are false.
At least one of these statements is false.
Each statement is either true or false. How many false statements did Agnes write on the paper?
Solution 1
We first number all the statements:
1) At least one of these statements is true. 2) At least two of these statements are true. 3) At least two of these statements are false. 4) At least one of these statements is false.
We can immediately see that statement 4 must be true, as it would contradict itself if it were false. Similarly, statement 1 must be true, as all the other statements must be false, which is established to be false by statement 4. As both 1 and 4 are True, statement 2 is true. Therefore, statement 3 is the only false statement, as there are three true statements, making the answer
.
-Rainjs
Solution 2
Statements
and
are true, while statement
is false. Hence, there are
true statements and
false statement. This result can be checked by examining the statements individually again.
Statements
and
will be true because there are
true statements. Statement
is also true because there is
false statement. Finally, statement
is false because there are
false statements.
~Tacos_are_yummy_1