Quantitative Aptitude - Arithmetic Ability Questions

ANS:      log₅512 = log512/log5  =  log29log10/2  =9log2log10-log2 =9*0.30101-0.3010 =2.709/0.699 =2709/699 =3.876

The given number series is 6, 8, 5, 10, 4, 14

6

6 + 2 = 8

8 - 3 = 5

5 + 5 = 10

10 - 7 = 3

3 + 11 = 14

...

Hence, the odd man in the given series is 4.

17th June, 1998 = (1997 years + Period from 1.1.1998 to 17.6.1998)
Odd days in 1600 years = 0
Odd days in 300 years = 1
97 years has 24 leap years + 73 ordinary years.
Number of odd days in 97 years ( 24 x 2 + 73) = 121 = 2 odd days.
Jan. Feb. March. April. May. June.
(31 + 28 + 31 + 30 + 31 + 17) = 168 days
168 days = 24 weeks = 0 odd day.
Total number of odd days = (0 + 1 + 2 + 0) = 3.
Given day is Wednesday.

The given series 

12   24   26.5   79.5   ?   330 follows a pattern that,

12 x 2 = 24

24 + 2.5 = 26.5

26.5 x 3 = 79.5

79.5 + 3 = 82.5

82.5 x 4 = 330

Hence, the missing number is 82.5

The given number series is 3, 12, 39, 120, 364

$$\begin{gathered} 3 \\ 3 + 32 = 3 + 9 = 12 \\ 12 + 33 = 12 + 27 = 39 \\ 39 + 34 = 39 + 81 = 120 \\ 120 + 35 = 120 + 243 = 363 (Not 364) \end{gathered}$$