In the following number series, two numbers have been put within brackets. Select the most appropriate option for these numbers in relation to their inclusion in the series.

21, 24, 19, (29), 17, 28, (15), 30

The first bracketed number (from the left) is incorrect and the second bracketed number (from the left) is correct.

21, 24, 19, (29), 17, 28, (15), 30

The logic;

21 →(-2) → 19    (difference between 21 to 19)

19 → (-2) → 17    (difference between 19 to 17)

17 → (-2) → 15    (difference between 17 to 15)

24 → (+2) → 26    (difference between 24 to 26)

26 → (+2) → 28    (difference between 26 to 28)

28 → (+2) → 30    (difference between 28 to 30)

Thus,

(29) should be 26

Therefore, The first bracketed number (from the left) is incorrect and the second bracketed number (from the left) is correct.