Introduction / Context:
This question asks you to move forward in time from a known date and weekday to another date in the next year. You must handle months of different lengths and track the total number of days passed. Once you know that total, you reduce it modulo 7 to find the resulting weekday. These techniques are widely used in calendar based aptitude questions.
Given Data / Assumptions:
- 18 March 1994 is a Friday.
- We need the day of the week on 25 February 1995.
- Year 1994 is not a leap year.
- Year 1995 is also a non leap year.
Concept / Approach:
The solution involves counting the number of days between the two dates and converting that number to odd days (remainder when divided by 7). We move from 18 March 1994 to 25 February 1995 step by step: complete the remaining part of 1994, then count days in 1995 up to the target date. After we know how many days have elapsed, we shift the weekday from Friday by that many days modulo 7.
Step-by-Step Solution:
First, count days from 19 March 1994 to 31 December 1994.
Days in March after 18 March: 31 - 18 = 13 days.
Full months April to December 1994 contribute:
April: 30, May: 31, June: 30, July: 31, August: 31, September: 30, October: 31, November: 30, December: 31.
Total for April to December = 275 days.
So days from 19 March to 31 December 1994 = 13 + 275 = 288 days.
Next, count days from 1 January 1995 to 25 February 1995.
January: 31 days, February: 25 days.
Total in 1995 up to 25 February = 31 + 25 = 56 days.
Total days between 18 March 1994 and 25 February 1995 = 288 + 56 = 344 days.
Odd days = 344 mod 7 = 1 (since 7 * 49 = 343).
So the weekday moves one day ahead from Friday to Saturday.
Verification / Alternative check:
You can quickly confirm: if 344 days correspond to 49 weeks plus 1 day, weekday must advance by one step only.
Friday plus 1 day is Saturday, consistent with the modular arithmetic.
Why Other Options Are Wrong:
Option A (Wednesday): Would require a shift of 5 days backward or 2 days forward from Friday, not supported by the count.
Option B (Monday): Would correspond to 3 days backward, again not matching the one day shift.
Option D (Sunday): Is two days ahead of Friday, not one.
Option C (Saturday): Correct, as it is exactly one weekday after Friday.
Common Pitfalls:
Miscounting the days in the months or including the start or end day incorrectly is common.
Some students attempt to jump entire years without splitting the calculation correctly at year end.
Ignoring the modulo 7 step and trying to track each month's weekday manually can also cause confusion.
Final Answer:
25 February 1995 fell on a Saturday.
Discussion & Comments