Reasoning Ability - Calendar Problems
What day of the week was 1st January 2000?
What day of the week was 1st January 2000?
easy Q11 of 15
Step-by-Step Solution
Step 1: Adjust month/year for Zeller
January → treat as month 13 of previous year. So use:q = 1,m = 13,year = 1999.Step 2: Compute K and J
K = 1999 % 100 = 99,J = floor(1999 / 100) = 19.Step 3: Evaluate formula components
floor(13*(m+1)/5) = floor(13*14/5) = 36;floor(K/4)=floor(99/4)=24;floor(J/4)=floor(19/4)=4;5*J = 95.
Sum:h = (1 + 36 + 99 + 24 + 4 + 95) = 259→259 mod 7 = 0.Step 4: Map result to weekday
Zeller mapping:0 → Saturday. So 1 Jan 2000 = Saturday.Final Answer:
Saturday → Option AQuick Check:
Known anchor: 1 Jan 2000 (Y2K) was Saturday ✅
Quick Trick: For Jan/Feb treat them as months 13/14 of previous year; apply Zeller and map 0→Sat.
Common Mistakes:
MISTAKES- Forgetting to decrement year for Jan/Feb or mis-mapping Zeller's h value.
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