Example 1 · level 1
Tenzin is thinking of a two-digit number. What is the number? I. It is odd. II. The sum of its digits is 3.
- Statement I alone is sufficient, but statement II alone is not.
- Statement II alone is sufficient, but statement I alone is not.
- Either statement I alone or statement II alone is sufficient.
- Both statements together are sufficient, but neither alone is.
- Even both statements together are not sufficient.
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- Statement I alone still allows 11 or 13 (and more).
- Statement II alone still allows 12 or 21 (and more).
- Both together fix the answer at 21.
- So: Both statements together are sufficient, but neither alone is.
Answer: Both statements together are sufficient, but neither alone is.