LINEUP LOGIC
Four number cards are arranged from left to right: 3 · 4 · 7 · 9. But not in that order.
WHAT’S THE ORDER?
Clues
- 3 is immediately to the right of 4
- 3 is somewhere to the left of 7
- 4 is not on either end
Answer
9 — 4 — 3 — 7
Why it works
The order is 9 — 4 — 3 — 7.
- Because 3 is immediately to the right of 4, the two cards form the block 4 — 3.
- The 4 cannot be on either end. If the block occupied the final two positions, 3 could not be somewhere to the left of 7.
- Therefore 4 — 3 must occupy the middle two positions. The 7 goes to the right of 3, and 9 fills the remaining first position.
- The order is 9 — 4 — 3 — 7.