Quantitative Aptitude - Arithmetic Ability Questions

Here the given series is 128, 32, 14, 2.66, 0.88

128 / 4 = 32

32 / 3 = 10.666

10.666 / 4 = 2.666

2.666 / 3 = 0.888

Hence, the odd man in the given number series is 14.

log 27 = 1.431
log33 = 1.431
3 log 3 = 1.431
log 3 = 0.477
log 9 = log(32)= 2 log 3 = (2 x 0.477) = 0.954

Here the given series 1, 6,  ?, 15, 45, 66, 91 follows a

Pattern in the series is, +5, +9, +13,...,.. +21, +25

So +4 is getting increased at every term addition.

Missing Number in the series will be 15+(9+4) = 15 + 13 = 28.

The series follows the following pattern.

4

16 = 42

37 = 12+62

58 = 32+72

81 ≠52+82.

Here every number is based on the digits of previous number. Hence, 81 is the wrong number in the given series.