Look at this series: 70, 71, 76, __, 81, 86, 70, 91, ... What number should fill the blank?

Look at this series: 70, 71, 76, __, 81, 86, 70, 91, ... What number s

1.	Look at this series: 70, 71, 76, __, 81, 86, 70, 91, ... What number should fill the blank?
Answer» In this series, 5 is added to the previous number; the number 70 is inserted as every third number.