Exams

As the sentence talks about the past it is apt to say. 'Had you been more careful ...'.

The given series pattern follows

17       9       10       18.5       35       90

× 0.5 + 0.5,   × 1 + 1,   × 1.5 + 1.5,   × 2 + 2,   × 2.5 + 2.5

So here 

17x0.5 + 0.5 = 9

9x1 + 1 = 10

10x1.5 + 1.5 = 16.5

16.5x2 + 2 = 35

35x2.5 + 2.5 = 90

Here the odd man in the given series is 18.5

$$\begin{gathered} 2 = 12 + 1 \\ 3 = 22 - 1 \\ 10 = 32 + 1 \\ Now 102 - 1 = 99 \\ 9802 = 992 + 1 \end{gathered}$$

Here in the given series, it follows a pattern that

77 + 2 = 79

79  - 3 = 76

76 + 5 = 81

81 -  7 = 74

74 + 11 = 85

Consecutive adding and subtracting of prime numbers.

So the wrong number in the given series is 75.

Here given 

2, 3, 6, 15, ? , 157.5

2 x 1.5 = 3

3 x 2  = 6

6 x 2.5 = 15

15 x 3 = 45

45 x 3.5 = 157.5

Therefore, the missing number is 45