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An exact gap
Keep two times linked by a stated difference.
Deduction: Exact-difference reasoning
GUIDED WALKTHROUGHStep 1 of 3
An exact gap
Each person has a different drink and snack. These small examples show one idea at a time; some squares will stay empty.
| Drinks | Snacks | Arrival times | |||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Tea | Coffee | Juice | Cocoa | Apple | Crackers | Brownie | Pear | 9:00 | 10:00 | 11:00 | 12:00 | ||
| People | Ada | ||||||||||||
| Ben | |||||||||||||
| Cy | |||||||||||||
| Dee | |||||||||||||
| Arrival times | 9:00 | ||||||||||||
| 10:00 | |||||||||||||
| 11:00 | |||||||||||||
| 12:00 | |||||||||||||
| Snacks | Apple | ||||||||||||
| Crackers | |||||||||||||
| Brownie | |||||||||||||
| Pear | |||||||||||||
Look here This step✓ Match× Not a match
The clues
- Ben arrived one hour after Ada.
- Ada did not arrive at 10:00.
STEP 1
List the possible pairs
Deduction: Exact-difference reasoning
Ada and Ben can arrive at 9:00 and 10:00, at 10:00 and 11:00, or at 11:00 and 12:00. Ada cannot have 12:00, and Ben cannot have 9:00.
Keep a note
Ada 9:00 → Ben 10:00 Ada 10:00 → Ben 11:00 Ada 11:00 → Ben 12:00