Question 1
Eight people attend seminars in four different months (January, March, May, July) on two dates (5th and 15th). Two people attend per month. The constraints are:
- W attends in March
- Q attends on the 15th
- Exactly two people attend between R and U
- V attends in the same month as T
In which month does R attend?
Step-by-step solution:
Timeline Grid Method:
1. Create month-date grid:
Jan 5 | Jan 15 | Mar 5 | Mar 15 | May 5 | May 15 | Jul 5 | Jul 15
2. Apply constraints:
- W in March (Mar 5 or Mar 15)
- Q on 15th (any month, date 15)
- Two people between R and U
(If R at position 1, U at position 4)
- V and T in same month
3. Systematic placement:
- Place W at Mar 5 (satisfies March constraint)
- Place Q at Mar 15 (satisfies 15th constraint)
- For 'two between' constraint: If R at Jan 5, U at Mar 15
- V and T together: May 5 & May 15
4. Verification:
All constraints satisfied with R in March
Key Strategy: Use grid to visualize all slots, apply direct constraints first, then deduce positions using gap constraints.
Timeline Grid Method:
1. Create month-date grid:
Jan 5 | Jan 15 | Mar 5 | Mar 15 | May 5 | May 15 | Jul 5 | Jul 15
2. Apply constraints:
- W in March (Mar 5 or Mar 15)
- Q on 15th (any month, date 15)
- Two people between R and U
(If R at position 1, U at position 4)
- V and T in same month
3. Systematic placement:
- Place W at Mar 5 (satisfies March constraint)
- Place Q at Mar 15 (satisfies 15th constraint)
- For 'two between' constraint: If R at Jan 5, U at Mar 15
- V and T together: May 5 & May 15
4. Verification:
All constraints satisfied with R in March
Key Strategy: Use grid to visualize all slots, apply direct constraints first, then deduce positions using gap constraints.