Question

What should come in place of the question mark (?) in the following number series?

64 54 69 49 74 44 ?

 (a) 89 (b) 69 (c) 59 (d) 99 (e) None of these

Answer 1

(e) The series is as follows:
64 + 5 = 69;
69 + 5 = 74;
74 + 5 = 79
54 – 5 = 49;
49 – 5 = 44