Question

Look at this series: 72, 76, 73, 77, 74, __, 75, ... What number should fill the blank?

Answer 1

 72, 76, 73, 77, 74, _78_, 75,

IN THIS THE NUMBER ADDED TO 4 AND SUBTRACTED WITH 3

Answer 2

Here's the number which goes into the blank

If we look at the series the we can finds that 4 is added and 3 is subtracted.

72+4=76

76-3=73

73+4=77

77-3=74

74+4=78

So the number which goes into the blank is 78