Explanation

For the first progression:

4, 20, 35, 49, 62, 74...

The differences between consecutive terms are:

20 - 4 = 16

35 - 20 = 15

49 - 35 = 14

62 - 49 = 13

74 - 62 = 12

85 - 74 = 11

Therefore, the next term in the series following 74 would be 85.