The last day of a century cannot be either

(A) Tuesday

(B) Thursday

(C) Saturday

(D) Sunday

Choose the most appropriate answer from the options given below:

(A), (B) and (C) only

1. Number of odd days in 100 years =  5 odd days

( 5 is code for Fridays )

So, Last day of the 1st century = Friday

2. Number of odd days in 200 years = (5 x 2) = 10  

\(\frac{10}{7}\) = 3(Remainder ) ≡ 3 odd days.

So, The last day of the 2nd century = Wednesday.

3. Number of odd days in 300 years = (5 x 3) = 15

\(\frac{15}{7}\) = 1(Remainder ) ≡ 1 odd day

So, The last day of the 3rd century = Monday

4. Number of odd days in 400 years = (5 x 4)  + 1 (leap year )= 21

\(\frac{21}{7}\) = 0(Remainder ) ≡ 0 odd days.

So, The last day of the 4th century = Sunday

Similarly , This pattern goes on.

 Hence, the last day of a century cannot be Tuesday or Thursday or Saturday.

Ans :- (A), (B) and (C) only