Quantitative Aptitude - Arithmetic Ability Questions

We know that,

Odd days --> days more than complete weeks

Number of odd days in 400/800/1200/1600/2000 years are 0.

Hence, the number of odd days in first 1600 years are 0.

Number of odd days in 300 years = 1

Number of odd days in 49 years = (12 x 2 + 37 x 1) = 61 days = 5 odd days

Total number of odd days in 1949 years = 1 + 5 = 6 odd days

Now look at the year 1950

Jan 26 = 26 days = 3 weeks + 5 days = 5 odd days

Total number of odd days = 6 + 5 = 11 => 4 odd days

Odd days :-

0 = sunday ;

1 = monday ;

2 = tuesday ;

3 = wednesday ;

4 = thursday ;

5 = friday ;

6 = saturday

Therefore, Jan 26th 1950 was Thursday.

The given number series is 90 72 56 42 36 20

9 x 10 = 90

8 x 9 = 72

7 x 8 = 56

6 x 7 = 42

5 x 6 = 30 (not 36) 

4 x 5 = 20

Hence, the odd man in the given number series is 36.

The given number series 2676, 445, ?, 21,6, 2, 1 follows a pattern that,

From right side,

1

1 x 1 + 1 = 2

2 x 2 + 2 = 6

6 x 3 + 3 = 21

21 x 4 + 4 = 88

88 x 5 + 5 = 445

445 x 6 + 6 = 2676

Hence the missing number in the given number series is 88.

504/42 × 7 - 63 + 28 = 84 – 63 + 28 = 49

Hence option 5 is correct.