117 ÷ 13 + 16 × 540 – 40 = 644

Checking option B,

117 ÷ 13 × 16 + 540 – 40

Applying BODMAS,

9 × 16 + 540 – 40

144 + 540 – 40 = 644 = RHS

Hence, option B is the correct answer.

The logic here is that the terms of the series increase by consecutive multiples of 3 –

39 + 3 = 42

42 + 6 = 48

48 + 9 = 57

57 + 12 = 69

69 + 15 = 84

84 + 18 = 102

Hence, option D is the correct answer.

The series is –

40 + 13 = 53

53 + 15 = 68

68 + 17 = 85

85 + 19 = 104

104 + 21 = 125

125 + 23 = 148

Hence, option A is the correct answer.

The series is –

R + 3 = U => U + 3 = X => X + 3 = A => A + 3 = D

J + 15 = Y => Y + 15 = N => N + 15 = C => C + 15 = R

X – 8 = P => P – 8 = H => H – 8 = Z => Z – 8 = R

U + 9 = D => D + 9 = M => M + 9 = V => V + 9 = E

Hence, option B is the correct answer.

The series is –

I + 4 = M => M + 4 = Q => Q + 4 = U => U + 4 = Y

O + 4 = S => S + 4 = W => W + 4 = A => A + 4 = E

Hence, option A is the correct answer.

The series is –

B + 3 = E => E + 3 = H => H + 3 = K => K + 3 = N => N + 3 = Q

Y + 3 = B => B + 3 = E => E + 3 = H => H + 3 = K => K + 3 = N

E + 3 = H => H + 3 = K => K + 3 = N => N + 3 = Q => Q + 3 = T

Hence, option A is the correct answer.

The series is –

12.8 + .7 = 13.5

13.5 + 1.4 = 14.9

14.9 + 2.1 = 17

17 + 2.8 = 19.8

Hence, option B is the correct answer.

The series is –

A => A => A => A => A

B – 4 = X => X – 4 = T => T – 4 = P => P – 4 = L

C – 8 = U => U – 8 = M => M – 8 = E => E – 8 = W

D – 12 = R => R – 12 = F => F – 12 = T => T – 12 = H

Hence, option C is the correct answer.

The logic here is that squares of consecutive natural numbers are alternatively subtracted or added to the terms to get the next terms –

72 – 1² = 71

71 + 2² = 75

75 – 3² = 66

66 + 4² = 82

82 – 5² = 57

57 + 6² = 93

Hence, option C is the correct answer.

The logic here is that the terms are increased by consecutive decreasing odd numbers –

68 + 11 = 79

79 + 9 = 88

88 + 7 = 95

95 + 5 = 100

100 + 3 = 103

Hence, option A is the correct answer.