How many such pairs of letters are contained in the word ‘DISCOURSE’, each of which has as many letters between them in the word as they do in the English alphabetical series (counting in both forward and backward directions)?

The correct answer is Two.

To find the pairs of letters in the word ‘DISCOURSE’ that have as many letters between them in the word as they do in the English alphabetical series (in both forward and backward directions), let us write down the position of each letter in the word along with its alphabetical position value:

Position 1: D (4)
Position 2: I (9)
Position 3: S (19)
Position 4: C (3)
Position 5: O (15)
Position 6: U (21)
Position 7: R (18)
Position 8: S (19)
Position 9: E (5)

Now, let us check all possible letter pairs counting in both forward and backward directions:

1. Pair R – S (Forward Direction):
In the given word, R is at position 7 and S is at position 8.
Number of letters between R and S in the word = 0.
In the English alphabetical series, R and S are adjacent (R, S), so the number of letters between them is also 0.

2. Pair U – S (Backward Direction):
In the given word, U is at position 6 and S is at position 8.
Number of letters between U and S in the word = 1 (the letter 'R').
In the English alphabetical series, between S and U lies the letter T (S, T, U), so the number of letters between them is also 1.

Checking all other combinations reveals no additional matching pairs.

Therefore, there are exactly 2 such pairs of letters (RS and US).